custom fields stopped working & more errors!

i am having a weird error in my WP install.

a few days ago, when i would write a new post, i would type the title in and then click into the text body area and the permalink would automatically update just beneath the post title field. for some reason this has ceased.

also, i use custom fields in the posts, which were working perfectly before, and now i can’t save them. i type the value in the field with the key selected, but when i go to click the add button nothing happens.

however, after i close this post and go back to the posts list it has automatically saved the draft of the post. very strange.

i am thinking it is a database error? i have tried repairing the tables via phpmyadmin but to no avail. the tables also show little or no overhead values.

any help would be greatly appreciated.