It might be too basic but are you sure the token 'type' is set up as a multivalue token?  Also, perhaps disabling the SDK Script activity and adding a Track Tokens activity to look at the value of the 'type' token that the script is using to see if the values look appropriate?

Hi Cliff!

Thanks for the reply. I've given your change a try, and unfortunately still yield the same issue. 

I had not considered that there might be a Type class in VB already (new to the language), so I've taken your recommendation and changed it to typeList instead.

Feel free to lob basic checks, it's always appreciated. I did make sure the token was set to multi-value, and I'm running the script from inside the VB editor so I can make sure the values entered are legitimate. 

I didn't think to run the script from the editor, in my test I published the workflow  and ran it to check for errors! 

When I run the script above from the editor it fails with the same error you report.  The help system indicates that you can enter a multivalue token in the editor by separating the values with a semicolon but that doesn't appear to work.

Does the script fail when you publish and run the workflow?

By running the script as part of the workflow, it sends a warning message to workflow, reporting that error. It doesn't run any of the code after that error (which is all of it, because this is the second assignment).

I put together a simple test workflow that retrieves a multivalue token and iterates through it reporting back each object type and value in the list object.

        Protected Overrides Sub Execute()
            'Write your code here. The BoundEntryInfo property will access the entry, RASession will get the Repository Access session
            Try
                ' Get MultiValue Token
                Dim lstTypes as List(of Object) = GetTokenValue("Type")
                ' Make sure the object is not null
                If lstTypes IsNot Nothing Then
                    ' Make sure there 1 or more items in object
                    If lstTypes.Count > 0 Then
                        ' Process each item in object
                        For iIndex As Integer = 0 To (lstTypes.Count - 1)
                            Dim sType As String = Nothing
                            ' Retrieve object type at index
                            Dim objType As Object = lstTypes(iIndex)
                            ' Cast object to string
                            sType = objType.ToString()
                            ' Report object index, type, and value to Workflow Messages
                            WorkflowApi.TrackInformation(iIndex.ToString() & ": " & objType.GetType().ToString() & " : " & sType)
                        Next
                    End If
                End If
            Catch ex As Exception
                ' Report error to Workflow Messages
                WorkflowApi.TrackError(ex.Message)
            End Try
        End Sub

Resulting messages when run:

I changed up my workflow and set it to read a multivalue field from a document.  I got the same error you see if the field only has 1 value.

Here is how I modified the code to handle MultiValue field with just a single value

        Protected Overrides Sub Execute()
            'Write your code here. The BoundEntryInfo property will access the entry, RASession will get the Repository Access session
            Try
                ' Get MultiValue Token
                Dim objTypes as Object = GetTokenValue("Type")
                ' Make sure the object is not null
                If objTypes IsNot Nothing Then
                    Dim sObjectType As String = objTypes.GetType().ToString()
                    WorkflowApi.TrackInformation(sObjectType)
                    Select Case objTypes.GetType().ToString()
                        Case "System.Collections.Generic.List`1[System.Object]"
                            Dim lstTypes as List(of Object) = GetTokenValue("Type")
                            ' Make sure there 1 or more items in object
                            If lstTypes.Count > 0 Then
                                ' Process each item in object
                                For iIndex As Integer = 0 To (lstTypes.Count - 1)
                                    Dim sType As String = Nothing
                                    ' Retrieve object type at index
                                    Dim objType As Object = lstTypes(iIndex)
                                    ' Cast object to string
                                    sType = objType.ToString()
                                    ' Report object index, type, and value to Workflow Messages
                                    WorkflowApi.TrackInformation(iIndex.ToString() & ": " & objType.GetType().ToString() & " : " & sType)
                                Next
                            End If
                        Case "System.String"
                            ' Handle String types
                            Dim sTypes as String = GetTokenValue("Type")
                            WorkflowApi.TrackInformation("0: " & sTypes.GetType().ToString() & " : " & sTypes)
                        Case Else
                            ' Handle Any other types
                            Dim oTypes as Object = GetTokenValue("Type")
                            WorkflowApi.TrackInformation("0: " & oTypes.GetType().ToString() & " : " & oTypes.ToString())
                    End Select
                End If
            Catch ex As Exception
                ' Report error to Workflow Messages
                WorkflowApi.TrackError(ex.Message)
            End Try
        End Sub