VB Script & NF - Error:Type Mismatch

I’m trying to get VB Script to connect to NF. It seems to be OK until I start calling handles eg “call CFRONT1.OpenTable(TH,270)”. I get Error:Type Mismatch:'CFRONT1.OpenTable’ie CFRONT expects the TH to be type long. can anyone help, has anyone got VBS working ? Tks JC