[Barabaika]

Ok. I've found the main problem.

Now it creates a query like this:
function/dbclass.php, line 85
SELECT user.userid,.... WHERE customavatar.userid=111111 OR user.userid=111111;

We don't need this at all, as it makes the query on all user table entries:
customavatar.userid=111111 OR

So, the WHERE statement in the line 85 should be:
WHERE user.userid=".$idneeded;

If it's difficult to understand, I'll create a diff file.

There is another "bad" query, I'll examine it later.