Failed opening required ' ./admin.php' or blank screen after login

Good morning

I have been trying all morning to log into my blog. When I try to log in I get a blank screen of death. If I don’t put my correct password in I get the correct error page. I have tried several fixes but am at a real loss on what to do.

This is the actual message I retrieved from my error log:

[28-Mar-2012 15:01:57 UTC] PHP Fatal error: require_once() [function.require]: Failed opening required ‘ ./admin.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/pstc8635/public_html/trucking_today/index.php on line 10

Any suggestions?

Thanks in advance