issue resolved... ? related to realplayer update.exe
I stopped the updater process of realplayer (in which folder the file was identified) on the startup menu, and then after restarting, when running AVG 2013 again the 'infected file' was not found.
I haven't gone back and restarted the realplayer updater... I don't use it anyway.
This may have been a false positive related somehow to the realplayer updater.exe, but don't know for certain...