Take a look at MSKB#Q129202 and MSKB#Q219022. Maybe they are relevant to your situation.

>Hello there! I hope everyone is having a great weekend!
>
>I have a question. Recently, we have been having a problem with tables being locked (usually they are not). A situation arose when trying to access a particular table exclusively, the system says it was locked. Well, no one was in the system at the time. This problem happens on more than one occasion. I tried to delete the files from the server, itself, but it would only let me delete the CDX file, but not the DBF. There is a sharing violation indicated, but all the systems were shut down at this point. Any conclusion as to why this is happening? We run both VFP 5 and 6 based applications.
>
>The system also says "attempting to lock, press ESC to quit" when trying to edit the locked table (but using the share function).
>
>Here are our specs:
>
>SERVER: NT 4.0 w/ 19GB HDD and 512MB RAM
>
>WORKSTATIONS: W2K: 128MB RAM w/ CELERRON 600MHZ and 19GB HDD
> 98 : 32-64MB RAM w/P2 233MHZ
> 95 : 32MB RAM with P2 233 MHZ
>
>Thanks!