[Mediawiki-l] Database errors getting worse

[sebastian n/a]

Lately I get a lot of Database errors..[see [mediawiki-l] Database Error 
when saving]
At first it seemed that restarting the whole thing took care of it, however 
now I encounter more and more of these errors.
As for now I can´t even access cerrtain pages without getting:
Warning: mysql_query(): Unable to save result set in 
/var/www/html/itwiki/includes/Database.php on line 312

No refresh or restart seems to fix this..
I´m running:
MediaWiki : 1.4.0
PHP       : 4.3.8 (apache2handler)
MySQL     : 4.0.20

Is there something I could do?
greetings