Hi, Gian.
I'm a newbie at this forum and only really joined yesterday after coming across the update problem that you refer to with Avast 5.0.377 Home (the free one).
After installing the software, it worked OK and did a full scan and fount two items of malware. However, when I tried to update it, it kept saying something like "Step 1 of 2 initializing....", and then nothing happened. The download bar starts to move but stops after about 2mm.
I uninstalled it and tried a clean installation but still can't update it.
I've given up for the moment and gone back to 4.8 which downloads updates no problem. I've decided to wait until they iron out the bugs on 5.0.377, which is a pity as I really like the new interface compared to the 4.8 version.
Sorry, I haven't got a solution, but at least you're not the only one with the problem. I hope they see our two posts and iron this out as soon as possible.
Regards,
David