Yep, the log page is the same URL!
It sounds like there's some problems in your mt.cfg.
QUOTE
the styles don't apply and the images don't show up
This is controlled by StaticWebPath
QUOTE
I get 404s when I try to create a new entry
Hmm. CGIPath?
Here's an mt.cfg for mysql database:
ObjectDriver DBI::mysql
Database name
DBUser name
CGIPath
http://www.you.com/cgi-bin/ StaticWebPath /mt-static/
Where do you have things set up?