You didn't answer the most important question and the one likely to be responsible for avast not running.
Did you uninstall Norton before installing avast ?
If avast sees any signs of Norton it will disable elements of the program so as not to cause a possible conflict, which could lock up your system.
So you need to uninstall the Norton trial, followed I would suggest the Norton removal tool.
The Outpost Pro 2008 is due an update that will remove this conflict (one from their side), how long it will take them to get around to it is anyone's guess. If you want to try OP Pro, you can resolve this conflict by uninstalling the Network Shield, that is what OP Pro is having a whinge about. Windows add remove programs, avast! Antivirus, Change/Remove, Change, find the Network Shield entry and uncheck it and OK your way out. That should resolve the problem until OP Pro fixes the problem on there side, it would be worth a reboot before trying to re-install OP Pro.
This issue will however be unrelated to the non starting of the avast providers.