Error while opening process - Gun adder

Everytime i try to attach AVA.exe to C.E it says " Error while opening this process".
I have 64-bit system and win7 and i use C.E 6.2.
Also ive tried MEAww's gun adder and the same thing happens.
Also if sum1 trustfull (e.g. MEAww or RedSpot) could add 2-3 guns for me I'd be very gratefull.
Thank you !