It started last night, and I still can't do anything once I get in...
The person who owns the domain is a friend of mine but doesn't seem to know a thing about WP, so I can't really ask her for help...
Yes, I checked my cookies settings and they seem fine.
Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, firstname.lastname@example.org and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.13 (Unix) mod_ssl/2.2.13 OpenSSL/0.9.8e-fips-rhel5 DAV/2 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/184.108.40.20635 Server at aeolusia.sea-meets-sky.com Port 80