I am trying to check in a document and I keep getting theerror "Object Doesn't support this property or method"

The document does get updated in the vault. What and why is thiserror being thrown.

pDoc = connection.CheckIn(MyWorkingPath + Part.Name, Part.Project,Part.Number, Part.Description, _
"Centering View", PDMWorks.PDMWRevisionOptionType.Default, " ",Part.GetStatus(), False, Nothing)

SolidworksApi macros