avast4ppc2005

Hi guys, avast antivirus for PDA does not support windows mobile 5. can anyone tell me the reason. I downloaded pocket pc version (avast4ppc_2005) onto my t-mobile MDA-PRO but. nothing happens. This is the error message I get "AVAST4PPC_2005_SETUP IS NOT A VALID POCKET PC APPLICATION. " , for short it does not work on tmoble mda pro or I-mate jasjar. Any help? Many thanks.
Paanii