YES!!!!! i am getting this on UBUNTU 10.10!
ok, i installed, no problem... started a scan, no problem... saw i needed to update, stopped the scan, ran the update PROBLEM... i forget what it said but it did not update and now i get the same message. i have removed, installed from RPM (error), DEB (same error as the OP), and TARBALL (error). is there a solution for this yet?
***EDIT***
Ok i just found this post,
http://forum.avast.com/index.php?topic=57775.msg487179#msg487179 and i was able to run without the error msg... but...when i update
avast! engine failed to reinitialize after database upgrade.
the application will now terminate now
and
An error occurred in avast! engine: Invalid argument
so this sounds like an update issue. since i just installed, does anyone know how i can update to the database before the latest?
***EDIT***
This post worked for me!
http://forum.avast.com/index.php?topic=57775.msg488889#msg488889