i can't uninstall my antivirus ? .... help

[fixxxer2012]

i have a sprint htc touch and i decided to try out and buy f-secure mobile antivirus. its ok, but it sorta slows my pda down and i want to free up some memory. i tried to uninstall it in the phone and by my pc's active sync connection and it wont budge "says it cant uninstall". i searched f-secures website and it does not say how to uninstall it for my 4.0 version. can i get some advice here guys, i also tried to reinstall the program " because it will first remove the duplicate" and that wont work either.

also ive read online we really don't need antivirus software on our pocker pc's. is that true ? ive hearda few people say to just try out a lightweight program like spybot pocket pc edition ? can you recommend a light weight / free scanner only, no real time protection.