I wonder if you have some strange routing or redirecting or url forwarding or something like that going on. I see that going to http://support.tsaadvet.com/ seems to redirect to http://support.tsaadvet.com/supportportal/
When I test with mojoPortal installed as a virtual directory application in a sub folder it works correctly and when I try it installed as a root level site it works correctly and when I add a folder based child site it also works correctly in the child site.
Your site does not appear to be a child site since I can tell from the csshandler url that the site id is 1. Using folder based sites only works if the first site is a root level site not in a sub folder. Since your site with site id 1 is in a sub folder, make sure you do NOT have this set to true in your Web.config or user.config
<add key="UseFoldersInsteadOfHostnamesForMultipleSites" value="false" />
It must be set to false if running the app from a virtual directory.
Hope it helps,