Avast cannot delete APK files

So my friend installed avast free on his laptop and ran a boot-time scan with PUP scan and it found Android:Gingerbreak-M [PUP] on his laptop he selected option 1(delete) and it cannot delete.
Then he selected put into virus chest it didnt placed it on virus chest.
Ignoring the infected file has let the scan continue.
My question is avast why cannot delete APK files?

PUP = not a virus/ Possible Unwanted Program

Google … android gingerbreak… and you find out what it is, a android root program