[TYPO3] plugins only show 'CODE' field, can't configure

[Valan]

I have a problem where if I add a plugin, like guestbook or feuser 
registration and I edit it, it will only show a 'CODE' field instead of 
the normal options. also, if I add the feuser registration plugin, it 
will cause the rendered page to be blank between the body tags until I 
remove the plugin. I can't figure out what could be causing this, does 
anyone know?