[TYPO3] error message with "front end user registration"

[Morten Kjems]

I have just setup "front end user registration" and everything works fine.
But I get an error message. Does anyone know why and and how I solve the 
problem?

I am not to good with php, so please help me out.

The error message.


Warning: mysql_fetch_assoc(): supplied argument is not a valid MySQL
result resource in
/var/www/fiskerifrakajak.dk/public_html/t3lib/class.t3lib_db.php on line 802

Warning: Cannot modify header information - headers already sent by
(output started at
/var/www/fiskerifrakajak.dk/public_html/t3lib/class.t3lib_db.php:802) in
/var/www/fiskerifrakajak.dk/public_html/typo3/sysext/cms/tslib/class.tslib_fe.php
on line 2853


regards
Morten Kjems