Can't delete posts or add/manage categories in Wordpress 2.3

I need some help re settings for my WP install. I am not able to delete posts or add/manage categories. Anyone else experienced this or know of a fix?

Thanks in advance

 

try disabling google xml sitemaps, or try disabling all your plugins and then adding 1 at a time until you find what one causes the problem.
most likely google sitemaps though...

 

Okay, I'll try the plugins