A problem with QueryString.php

[anda]

About a month ago my forum started to give me this error:

Code Select Expand

Notice: Undefined variable: sourcedir in /var/www/userhome/ciferial/sites/shinatrya.net/www/menthal27/keskustelu/index.php on line 49

Warning: require_once(/QueryString.php) [function.require-once]: failed to open stream: No such file or directory in /var/www/userhome/ciferial/sites/shinatrya.net/www/menthal27/keskustelu/index.php on line 49

Fatal error: require_once() [function.require]: Failed opening required '/QueryString.php' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/userhome/ciferial/sites/shinatrya.net/www/menthal27/keskustelu/index.php on line 49

I thought there was a problem with the current theme, so I reinstalled the forum and restored backups. I also changed the mod Advanced Visual Verification to Visual Verification Options. It helped at that time, but in a few days the same error appeared and I had to reinstall the forum again.

This was about two weeks ago. Now the same error has appeared again and I just don't understand, why.

At the moment the forum is using the default theme without mods, but it seems it is just a matter of time when this error will come again since also other forums in the same server have had the same problem. What should I do? Why does this error keep popping out? And mos importantly, how can I eliminate it?

[Rumbaar]

Have you tried to upload a fresh version of the QueryString.php to your source folder?

Be sure to take a backup of the current file you have in there.

[anda]

Yeah, I tried that when the error came the first time. It didn't have any effect, but reinstalling the forum helped, temporarily.

The weird thing is that the error keeps popping up with no visible reason, even if I have only the default installation with no extra themes. I also changed the used mods between the errors, so it seems they aren't causing the situation. The problem can be temporarily fixed by making a fresh install and changing the database table information to the old ones from the forum's admin panel.

There doesn't seem to be any logic in the time between the errors, either. The error came the first time in the beginning of December, then two days later and now about two weeks later. I guess there has to be some variable that causes this, but so far I haven't been able to figure out what it is.

There hasn't been any problems with previous versions of SMF.

[Rumbaar]

If it's an error like that, I can only surmise that it is somehow related to your host.  File corruption or something like that.