Can't install 5.0 on all our PC's want to go back to 4.8

Our previous 3 yr license expired which was currently running v4.8 - so I went online and purchased the Internet Security 5.0 (3 PCs, 1 year) x (2) since we have 6 pc’s. Only 1 computer took the upgrade to 5.0 with no issues. 2 other computers eventually got 5.0 installed - but not without problems, and the other 3 computers could not install at all. The 3 computers that did mange to install 5.0 ran significantly slower across our network, VPN wouldn’t work, file details not displaying fast enough, other various problems such that it wasn’t worth trouble shooting 5.0 any long (as we already lost several hours of down time trying to upgrade to 5.0) so we un-installed 5.0 on all our machines. Well now I want to go back to 4.8 - but the new license file that Avast came up with won’t work - I thought was just going to be able simply installing a new license text code. I’ve already submitted a ticket through Avast online support - but that was over a week ago.

Did I just waste my money upgrading to 5.0?

Which version were you trying to install?
Here’s the link to the latest build: http://forum.avast.com/index.php?topic=58183.0
Some installation issues are fixed with this version.
asyn