>I just found that an ASP.NET application is locking DBF files as soon as we use them. I can go in VFP and use the table exclusive as long as I don't start my ASP.NET application. As soon as I did one hit on that site, I can no longer update the structure of my DBF. I have to reboot everytime I want to update the structure. Is this normal?

Michel,
I believe it's related with connection pooling in IIS.
Would you try adding:
OLE DB Services = -2 (or -4)
to your connectionstring.
Cetin