You also need to tell us what colFields is. Is it a function? If so, native or user defined? Or is it a data structure of some sort, defined by you? I suspect colFields is defined like this

 Dim colFields As MAPI.Fields

- a MAPI object - in which case I suggest Win32::OLE , specifically the section "Hints for Microsoft Office Automation" may be a possible approach. Hope this helps.