Hi,
I recommend read the notes about moving a site:
http://www.mojoportal.com/moving-an-installation-of-mojoportal-to-a-different-server.aspx
also I recommend checking the logs for any related errors or clues:
http://www.mojoportal.com/basic-troubleshooting.aspx
and you can also use tools like the Firebug plugin for Firefox to see what is going on with css and images, whether they are returning a 404 etc.
Hope it helps,
Joe