Page load error

Hi I’m having a problem with wordpress 2.02. Everything is working ok, except when I try to edit things in my admin page, It lets me change things, but after I press update, or publish, or whatever I am doing it executes my command but then brings me to a blank screen, it doesn’t return to the section i was in like it should. It just executes and goes blank. Also the same thing happens when people try to login, I can’t figure out why it does this, if you could help me I would appreciate it, thanks.