My blog administration page is coming up blank-Plz Help!

I called my user support, which is yahoo and they said it was nothing on thier end but told me how to find the error logs. This started 2 days ago after I installed a few new items. I’m new at this and am very frustrated. Please help! Here are the codes that are coming up; PHP Warning: Cannot modify header information – headers already sent by (output started at /blog/wp-content/plugins/wordpress-facebook-integrate/wp-fbi-core.php:28) in /blog/wp-login.php on line 337 [06-Jan-2011 12:41:59] PHP Warning: Cannot modify header information – headers already sent by (output started at /blog/wp-content/plugins/wordpress-facebook-integrate/wp-fbi-core.php:28) in /blog/wp-login.php on line 349 [06-Jan-2011 16:21:04] PHP Warning: Cannot modify header information – headers already sent by (output started at /blog/wp-content/plugins/wordpress-facebook-integrate/wp-fbi-core.php:28) in /blog/wp-includes/pluggable.php on line 890