Are you saying that you're using an old version of g-data that still uses the 4.x engine (or why are you mentioning avast 4 at all)?
This particular detection is classified as a PUP (which cannot be seen in VirusTotal results as it omits the suffix for some reason), and avast! 4 doesn't detect PUPs because it's missing the necessary configuration options. Whether the g-data version on VirusTotal is an old one, based on avast! 4 engine, or if g-data doesn't enable PUP detection in avast! 5 engine... don't know.
As for why not ending the support for 4.8... well, all of the existing pre-2012 editions of g-data would stop working (or more precisely, updating), for example, right?
Btw, last warning: unless you change your tone, you will be banned again, this time for good. You are certainly not the one to call the others bullies.