After upgrading to Wordpress 3.0, I can't put anything inside functions.php without errors

I upgraded to version 3.0 and all was great. Then, I installed the plugin 'Post Links To'. I noticed then I couldn't log out without getting a white page, I also couldn't update things. Some of the dashboard still worked but it was a real problem.

I then deleted the plugin but the problem remained.

The weirdest thing is, if I change theme, or remove everything from my开发者_StackOverflow社区 functions.php in the theme I want, it works again.

I made the theme on 2.9 and it also worked in 3.0 before that plugin.

Any help is hugely appreciated.

Henry.

EDIT: here is the paste bin: http://pastebin.com/GMpPEm4T

Stop closing and opening the PHP brackets. The newlines are being echoed to the browser, sending the headers way before WordPress is ready. Here's a pastebin that should work:

http://pastebin.com/wdyMELvP

General rule of thumb: never close PHP in the middle of the file unless you're inside a function declaration or a conditional.

remove any whitespace in the file.