3
I'd try the things below to see if it helps:
1) Clear your ./templates folder (except for the index.html file) and the ./cache folder (except for the adminmenu.php file).
2) Check the settings on both ./cache and ./templates_c... I've seen instances where not having the rights configured correctly (CHMOD 777) cause similar issues. I'd check the rights on your ./uploads folder while you're at it - but I don't think this is causing the problems you're seeing...
3) Try using the default themes/templates if you've changed them. Sometimes these can cause issues...
4) Turn on debug (ADMIN > PREFERENCES) and report back here with any messages you get.