Fatal Error When Accessing Posts and Pages in Dashboard

Ok, I have alot of pages in my blog and every time I create a new one it appears to bring my entire blog down as in completely inaccessible.

Now while I am able to access the dashboard and most of the functions, I can’t access the posts, pages, or even the permalink option without gettting this error –

Fatal error: Maximum execution time of 30 seconds exceeded in /mounted-storage/home26a/sub001/sc23157-XQLB/www/wp-includes/classes.php on line 996

In case you were wondering, line 996 reads like this:

$rewrite_rules = array_merge($rewrite_rules, $this->generate_rewrite_rules($page_structure));

It’s virtually the same every time. I’ve contacted my host and they say it’s a script problem even though I just did a fresh install of Worpress to try and fix it. Funny thing is, I couldn’t even run the upgrade without getting that error and then suddenly, almost randomly, it worked and I was able to access everything again.

I’ve searched and tried to solve this problem for almost 24 hours now. Any help would be greatly appreciated.