Hello aranders3 and welcome to the forum.
1. What is your firewall (FW) and is anything from your FW blocking Avast?
2. Are you getting any kind of error message from Avast, like a yellow "!" or red "X" over the Avast toolbar on the bottom of your screen, or "Your system is not secured" on the GUI?
3. Have you changed any of the default settings in the GUI?
4. Did this problem just start? Are you having any other problems as well?
5. What is your OS, 32 or 64-bit?
6. What version of Avast did you install? 5.0.677 is the latest version.
7. What product of Avast did you install? Free, Pro, AIS?
8. What other security software do you currently have or did you have in the past on this machine including antivirus (AV), firewall (FW), and other security programs?
9. How do you connect to the Internet?