A user transaction is already in progress

Hi,

I'm developing a Web Service (using Delphi 6), working with ODAC components.
In some cases, I receive the error message "A user transaction is already in
progress". I'm not using BDE, but this message is listed as a BDE error
message.
How can I solve this problem? Is this message a Delphi bug, or not?

Thanks,

Carlos Alexandre