Are all of you reporting this problem in this topic using Dells ?
Does it relate to Dell Wireless WLAN Card ?
If so there are a couple of topics about this already,
http://forum.avast.com/index.php?topic=68702.0 for one.
Have both of you tried what was suggested in the above topic by NON, uninstall the behaviour shield element ?
Windows add remove programs, Avast xxx, click the Change/Remove button, click the Change section from the new window and uncheck the Behaviour Shield entry, OK your way out and reboot.