I too was running into this problem in version 4.1 of the framework. I thought it was that line of code causing that problem and kept banging my head against the same wall. The actual problem I found was that i was using FOXUSER.DBF exclusive against someone elses FOXUSER.DBF. This may not be your remedy but it sure sound very familiar. Make sure you're not trying to accessing another file on the network. I thought I wasn't and it turned out I was.