Lets first check if the DB has that AV defs information... In the clients tab, when you change the "view" to Protection technology, you should be able to see the virus defs column... is it populating some information?... And also, try to get a computer status log from monitors-> logs... what does it say?
And oh, if the return code =1 for LU, the problem could be with the inventory or settings files of liveupdate.... Try running LUALL from the run command... It would give you more detailed error code which would help us... And before you do so, please goto control panel > Symantec LiveUpdate and change few things...
* Change mode to 'interactive' and error level to enhanced....
One last question, are the SEPMs replicated?
Cheers,
Visu.