[AccessD] A2K: Transfer Database

hello all
can anyone tell me why the acLink version of transfer database 
below works but the import version fails? Along with the error message 
"Cannot define Field more than once"
I have tried every combination I can think of in relation to the dbf file name location etc.
No joy and the help is useless

'This one works fine
DoCmd.TransferDatabase acLink, "dBase IV", "C:\", acTable, "C:\SIDS.dbf", "tblStudents", False
'This one fails
DoCmd.TransferDatabase acImport, "dBase IV", "C:\", acTable, "C:\SIDS.dbf", "tblStudents", False

many thanks

Drren