What worked for me:
AVG free ed. 7.5
Windows XP
1) Go to Virus Vault and delete the two "viruses" from the Poker Office folder
2) Run the most recent patch of Poker Office (2.35)
3) Reboot
4) Replaced the file "pnthandler.dll" with the modified one from admin. (See page 8 of this thread)
5) Run Poker Office
Poker Office now opens although AVG still treats the other file as a virus.
Have only tried to open Poker Office, so do not know how it performs when actually playing poker, and have neither tried to open Poker Office again. (Since I do not plan on playing poker tonight

)