I started getting the general error message when I tried to update the data files for AVG 2010 Free Edition, having used the previous ones since inception very successfully. So, I decided to update to 2012 instead.
I could not delete the old version , update to the new, get datafile updates without having to reboot (which seemed to get rid of the general error until the next attempt to get the new datafile, so quite a pain)
For this error resolution(I am using AVG 2012 Now) I had to follow these steps. PC is currently running Windows XP SP2
So, OPEN the COMMAND PROMPT (START/ PROGRAMS/ ACCESSORIES). Note the first two commands typed in did not give any response, just moved to the next line, having executed the command. The final two commands did bring a response message to verify the command given.
First, you ensure the MS Windows Installer service is correctly installed: Remember to include the space before the forward slash. Typing is case sensitive, as entered below, by typing:
REMEMBER THE SPACE BEFORE THE FORWARD SLASH
Press ENTER on the KEYBOARD
Next, type in
remembering the space before the forward slash and press RETURN again
Next, you need to ensure the Windows Installer service is not disabled by typing
NET STOP MSISERVER
YES, In CAPITALS, then press enter,
then NET START MSISERVER
again pressing enter.
Close the COMMAND PROMPT window and try your required update again. PLEASE NOTE- I decided to delete the old version, which I could not do before when I tried, which worked and I was able to install the newest version, 2012 after that. I dare say if I had just tried to update the older version this should have worked also, I just tried the delete first.
Hope this helps.