OneCare's firewall does not block or allow IP address ranges. OneCare allows and blocks programs.
If you open the OneCare firewall settings -
open OneCare, change settings, firewall, advanced - you can see programs that are blocked or allowed. You can change that here. Additionally, on the ports and protocols tab, you can add settings that the vendor of the chat program tells you may be needed to allow their program to work. However, the information you provided above mentions nothing about ports and protocols, only IP ranges. If your chat dashboard and program function in your web browser and the web browser is accessing the Internet fine, then the browser is being allowed through the firewall.
if you want to confirm that it isn't the OneCare firewall, turn off the firewall temporarily via the Change Settings/Firewall tab. If the chat program now works, please contact the chat provider and/or OneCare support for help with configuring the ports and/or protocols and perhaps the program file needed to be allowed in the settings. I suspect, however, that turning off the firewall will not make a difference.
How to reach support (FAQ) - http://social.microsoft.com/Forums/en-US/onecareinstallandactivate/thread/30400b52-7f26-4ba0-bc18-17e305329d90
-steve
Microsoft MVP Windows Live / Windows Live OneCare, Live Mesh, & MS Security Essentials Forums Moderator