I went to Network Proxy and I entered my proxy setings. If I then open a terminal and run env | grep proxy I see all the pertinent proxy information. From the same terminal, if I run wget google.com it grabs the page just fine.
However, if I try and run Firefox with "System configuration settings" selected under Network Proxies, then it won't load web pages. Additionally, the package manager is not able to access the servers. If I change Firefox and manually setup the proxies, pages load fine (and I'm using FF under Mint 14 to write this post).
It seems like the Network Proxies isn't setting up properly across the system. I tried running sudo apt-get from the aforementioned command line (with the confirmed environment variables), but that still doesn't work. My assumption is that the package manager is looking for something else for proxy setup, or something is just messed up altogether.
Thanks for your help