Database question!
 

If I delete a table in the database will it be re-added when I upgrade my vbulletin?

All my users gets a HTTP 500 error when they try to upload pictures to their albums. I contacted vBulletin and they tried to help but they told me to contact my host. From There I contacted my host and after they tried for 3 days they said there's nothing they could do.

About the first question i'm not 100% sure, so i'll leave someone else that is 100% sure to answer that one.

In general i would say the http 500 could be as result of directory permissions.
Check if the upload folder has proper permission. (see chmod on linux, more info can be found here: http://en.wikipedia.org/wiki/Chmod )

I actually reset the tables instead but it didn't help.

I did chmod them all in detail but that didn't help, my host even did it and it didn't help at all, I'm lost here.

Is your host using mod security?

Ummm... What?

<a href="http://www.modsecurity.org/" target="_blank">http://www.modsecurity.org/</a>

No they do not.

Isn't this your post - http://www.vbulletin.com/forum/showthread.php?t=307874 Is this the same issue where you deleted the table and your host can't fix it for 3 days? Or is this a different issue?