I've been having some major problems with my Drupal website recently. Hoping someone here might be able to help...

As posted here, I'm having a problem with Drupal's permissions. Basically, I can't edit or save new permissions - I tick the boxes and hit Save, but when the page reloads, there's no confirmation message saying the changes have been saved, and the changes I made have been reverted back to how they were before.

Another problem I've been having (as posted here), and which I think may be connected to the above problem, is arranging menu items by dragging them on the Site Building > Menus > [menu name] page. I can drag the menu items around, but similar to the permissions problem above, when I hit save, the menu items are back to their original positions. Interestingly though, I can successfully change their positions by manually setting their weight value on the Edit page...

I thought it might be a problem with the database getting full (cause the problems occur when saving changes to the database), but my web host says that shouldn't be an issue (other clients have databases in the gigabytes, while mine is only about 30MB).

Any and all help would be greatly appreciated!