Copy item from single-select to multi-select.

Hello, this is my first post, so thanks up front for whatever help anyone can give, and sorry for my lack of knowledge.

I am trying to copy the selection in a single-select property (iRollNumberProperty) to the selection in a multi-select property (iLandIDProperty) on the same object. The properties pull from two different Object Types which use identical queries to pull from the same external source (so, the unique IDs are the same in both Object Types).

I borrowed the AddUpdateProperty function from another topic, and used it without modification. The code is in the automatic value of an unrelated field.

I have used one specific case (129203000) to troubleshoot. The idea is to add the objectID "129203000" to the Land ID property to the object I was using as a test. When I trigger it, I get the error message that is attached. 344 is the ID of the Land ID object type, which is where the property value should be pulled from.

Hopefully my code will fill in the gaps where my explanation may be lacking. This is M-Files 2015.3.

Thanks.

Option Explicit

 Dim iRollNumberProperty : iRollNumberProperty = 1432 '1432 is the Roll Number Property Definition
 Dim iLandIDProperty : iLandIDProperty = 1747 '1747 is the LandID Property Definition
 Dim objClientLookup: Set objClientLookup= PropertyValues.SearchForProperty(iLandIDProperty).TypedValue.GetValueAsLookup()

if IsNull(PropertyValues.SearchForPropertyEx(iLandIDProperty, true))=False then

    dim iRolls: iRolls = 129203000
    AddUpdateProperty iRolls, iLandIDProperty

end if


Function AddUpdateProperty(sValue, PROP_ID)

	Dim oProperty : Set oProperty = CreateObject("MFilesAPI.PropertyValue")
	oProperty.PropertyDef = PROP_ID
	Dim iDataType : iDataType = Vault.PropertyDefOperations.GetPropertyDef(oProperty.PropertyDef).DataType
	Dim iValue : iValue = CLng(sValue)			
	Dim oLookups : Set oLookups = PropertyValues.SearchForProperty(PROP_ID).TypedValue.GetValueAsLookups()
	Dim oLookup : Set oLookup = CreateObject("MFilesAPI.Lookup")
	Dim oCount
	
	oCount = oLookups.Count	
	If oCount <> 0 then oCount = oCount + 1
	oLookup.Item = iValue
	oLookups.Add oCount, oLookup
	PropertyValues.SearchForProperty(PROP_ID).TypedValue.SetValueToMultiSelectLookup oLookups
	oProperty.TypedValue.SetValueToMultiSelectLookup oLookups
	Vault.ObjectPropertyOperations.SetProperty ObjVer, oProperty
End Function