Roger,

> Hi - looked at the log - there are entries like:
>
> "Access Violation - The code attempted to access a virtual address
> without privilege to do so. the exceptioi will cause the Firebird
> server to terminate abnormally"
>
> Which it did and re-started
>
> I believe this is because the server has hyperthreading switched off

NOPE! Superserver runs better with Hyperthreading turned off.

> (make FB run faster?) but the db uses UDF's (the std firebird ones)
> and there may be a threading issue if a call is being made to the
> same UDF by more than one user at the same time.

The error is very likely due to a bad UDF.

Please confirm the exact Firebird version and UDF library name/version
you are running.


Sean