Accesing variable form reference object VB Script

Try this:

Option Explicit

Dim postavke
set postavke = PropertyValues.SearchForProperty(1283).TypedValue.GetValueAsLookup().GetAsObjVer

Dim uvjet : set uvjet = Vault.ObjectPropertyOperations.GetProperties( postavke, True )
                                                                                                                     

If uvjet.SearchForProperty(1282).TypedValue.DisplayValue = "Yes" Then
    AllowStateTransition = True
Else
    AllowStateTransition = False
End If

When you get an error you need to look carefully in the full error description. You will be able to find which line in your code creates the error. That is quite helpful in debugging - especially if you combine it with careful use of the API documentation https://developer.m-files.com/APIs/COM-API/Reference/

DocumentCache.cpp, 7599, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
DocumentCache.cpp, 19402, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCMethodCallWithRetry.h, 27, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCMethodCallWithRetry.h, 27, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperations.cpp, 11362, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperations.cpp, 5540, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
MCallInLoop.h, 521, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperationsHelper.cpp, 1995, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperationsHelperPrivate.cpp, 212, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperationsHelper.cpp, 9630, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperationsHelper.cpp, 10831, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperationsHelper.cpp, 11087, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperationsHelper.cpp, 25849, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperationsHelper.cpp, 25979, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperationsHelper.cpp, 9647, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperationsHelper.cpp, 11087, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
RPCDocumentOperationsHelper.cpp, 25791, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
StateTransitionManager.cpp, 263, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
StateTransitionManager.cpp, 1050, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
VaultScriptSessionTemplates.cpp, 275, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
VaultScriptSessionTemplates.cpp, 340, Script execution failed. ((State transition (ID: 153), StateTransitionValidation: 36-2)) (0x800408BB)
VaultScriptSessionTemplates.cpp, 340, Not found. (ID: 1) (0x8004000B)
VaultScriptSessionTemplates.cpp, 523, Not found. (ID: 1) (0x8004000B)
CoActiveScriptSite.cpp, 897, Not found. (ID: 1) (0x8004000B)
CoActiveScriptSite.cpp, 739, Not found. (ID: 1) (0x8004000B)
State transition (ID: 153), StateTransitionValidation, 6, Not found. (ID: 1) (0x8004000B)
MNullPropagatingDispatchImpl.h, 127, Not found. (ID: 1) (0x8004000B)
MNullPropagatingDispatchImpl.h, 174, Not found. (ID: 1) (0x8004000B)
CoVaultObjectPropertyOperations.cpp, 345, Not found. (ID: 1) (0x8004000B)
ServerVaultObjectPropertyOperationsHelper.cpp, 77, Not found. (ID: 1) (0x8004000B)
RPCObjectOperationsHelper.cpp, 34, Not found. (ID: 1) (0x8004000B)
CoRPCOverCOM.cpp, 6935, Not found. (ID: 1) (0x8004000B)
RPCDocumentOperations.cpp, 6382, Not found. (ID: 1) (0x8004000B)
MCallInLoop.h, 521, Not found. (ID: 1) (0x8004000B)
RPCDocumentOperationsHelper.cpp, 5800, Not found. (ID: 1) (0x8004000B)
RPCDocumentOperationsHelper.cpp, 5838, Not found. (ID: 1) (0x8004000B)
RPCDocumentOperationsHelper.cpp, 14356, Not found. (ID: 1) (0x8004000B)
RPCDocumentOperationsHelper.cpp, 14584, Not found. (ID: 1) (0x8004000B)
RPCDocumentOperationsHelperPrivate.cpp, 12559, Not found. (ID: 1) (0x8004000B)
RPCDocumentOperationsHelper.cpp, 28811, Not found. (ID: 1) (0x8004000B)
RPCDocumentOperationsHelperPrivate.cpp, 11476, Not found. (ID: 1) (0x8004000B)
(M-Files 23.9.12966.6 2023-11-02T06:36:26.710Z)

Note this line:
State transition (ID: 153), StateTransitionValidation, 6, Not found. (ID: 1) (0x8004000B)

The error origins from line 6 in the code.
"Not found" probably means that the variable "postavke" did not provide the required input. So, you need to go back to line 4 and figure out what is wrong there.
It could be that a simple "()" is needed after GetAsObjver as suggest in the documentation.
It could also be that property 1283 is not a single select lookup property, or that the property is empty on the current object. I can't tell from the info available here, that is something you need to work on.

Option Explicit

Dim postavke
set postavke = PropertyValues.SearchForProperty(1283).TypedValue.GetValueAsLookup().GetAsObjVer()

Dim uvjet : set uvjet = Vault.ObjectPropertyOperations.GetProperties( postavke, True )
                                                                                                                     

If uvjet.SearchForProperty(1282).TypedValue.DisplayValue = "Yes" Then
    AllowStateTransition = True
Else
    AllowStateTransition = False
End If

To me it all checks out. Only the code could be the issue. I belive the objVer "Postavke" is taken I beleve so because it is searching for ID 1 but when i use it to search property it points to no object type or wrong one so it gets "not forund".

I have tested it by using 

Dim OV : set OV = Vault.ObjectOperations.GetLatestObjVer( postavke.objID, false, false )
So problem is with ObjVer that i get from Postavke its missing something.

working code looks like 

Option Explicit

Dim postavke
set postavke = PropertyValues.SearchForProperty(1283).TypedValue.GetValueAsLookup().GetAsObjVer()

Dim OV : set OV = Vault.ObjectOperations.GetLatestObjVer( postavke.objID, false, false )

Dim uvjet : set uvjet = Vault.ObjectPropertyOperations.GetProperties( OV, True )
                                                                                                                     

If uvjet.SearchForProperty(1282).TypedValue.DisplayValue = "Yes" Then
    AllowStateTransition = True
Else
    AllowStateTransition = False
End If

I belive this is a bug. Where do i report something like that?

I do not agree that this is a bug.
The problem is perhaps that you set True as the last variable in line 6
Dim uvjet : set uvjet = Vault.ObjectPropertyOperations.GetProperties( postavke, True )
This forces the code to check the properties from the server. If the object has not been checked in at this point there will be no properties to find on the server. Try setting it to False in stead.

I do not agree that this is a bug.
The problem is perhaps that you set True as the last variable in line 6
Dim uvjet : set uvjet = Vault.ObjectPropertyOperations.GetProperties( postavke, True )
This forces the code to check the properties from the server. If the object has not been checked in at this point there will be no properties to find on the server. Try setting it to False in stead.