[Martin_S]

Thank you for your answer. I have read the manual before asking. But I can't find any help there for my problem. The mentioned reasons in the manual:

1. Is that the server timed out and closed the connection. By default, the server closes the connection after 8 hours or 28800 seconds if nothing has happened. You can change the time limit by setting the wait_timeout variable when you start mysqld via your server's /etc/my.cnf as well.

The statement is in my case very short (no join, selection of one row of a table with two rows). All other statements of vbulletin (which are much more expensive) work without an error.

2. Another common reason to receive the MySQL server has gone away error is because you have issued a ``close'' on your MySQL connection and then tried to run a query on the closed connection. You can check that the MySQL hasn't died by executing mysqladmin version and examining the uptime.

All other statements work at the same time without an error.

3. You can also get these errors if you send a query to the server that is incorrect or too large.

In phpmyadmin the statement works without an error.

4. Or simply your host restarted MySQL. I'd contact your web host and ask him to look into this.

That's not possible if the error only occurs on this statement...

So - any ideas?

Martin