avast free for Mac 2.74 -- "Engine Cannot Launch" error after installation

I just downloaded avast free for Mac (v2.74) from the apple downloads site and installed it but it won’t run. After successful installation, nothing happens. When I try to run avast from the applications folder, an error pops up:

“Engine Cannot Launch: The virus scanner engine cannot launch: try please to re-install the application, or consult the support”

Only option is to click the “Terminate button”

I’m running Mac OS X 10.6.3 and have attempted to reboot and reinstall several times. Any idea why the software won’t work?

-Michael

you fiend the Linux / Mac forum here
http://forum.avast.com/index.php?board=5.0

or nr 5 from the top
http://forum.avast.com/index.php