often the update manager says i don't have an internet connection and stops working. I check and do have access to the internet.... I think it might have something to do with updating google chrome because it usually does this when updating chrome.
You can optionally run in the terminal
Watch both those commands and you will find the issue. Post back and we can debug further.
Optionally once you find the issue you can disable that software source by going into your Update Manager and clicking settings and then going into "Other Sources" if it turns out to be a non-Ubuntu issue and an application installed on Ubuntu like Google Chrome. My Chrome install uses this URL http://dl.google.com/linux/chrome/deb/