Now that I'm a little more awake, I should've mentioned that getting to
the login page is no problem for FF or IE. The problem is that after
entering a valid userid and password, IE gets the Access Denied message.
When I browse to
http://www.cardenasdow.us/drupal5
on FF2 or IE6 on Win 2K or FF3, IE7, or Safari Beta on Windows Vista,
it works every time.
Are you running IE7 on Xubuntu or on Windows? Because on Linux, IE7 is
only a beta.
HTH.