That is weird because the tablets at this site: http://www.linkcomputers.com/ultratbltpc.html use Windows XP Tablet and they use Symantec Norton Antivirus 2003. I think someone is misleading you or they don't know what they are talking about.
And as a matter of fact, almost ALL of the searches I did on google.com for Antivirus on Tablet PC, said they were able to use Norton Antivirus 2003.
When I try to install the program I get an error message:
"Error 1326 Error Getting File Security"
"c:\windows\system32\drivers\savrt.sys GetLastError: 5"
The title in the errow window is Installer Information.
Do I have something else going one?