Help!!!!!!!

I have a drupal website up at richmondadultentertainment.com when users go that address it forwwards with masking to 173.14.119.153 when users go to the domain name for some reason with internet explorer i am having a problem with users logging in you can login but once you do it does not give the login succesful splash and does not take away login block but does show user logged in under who online but if you go directly to ip it seems to work fine however in safari you can go to either works great . I have cleared all cache several times i have had people go who do not have a browser cache at all of site have same results i never pointed and setting to the ip i am running default settings for the most part i created a test login: guest pass: guest if anyone has the time to check this out and lead me in any direction i would greatly apreciate it i am totally confused on what is the cause if its a browser or serverside issue