When using Eclipse (Indigo) earlier today, I ran into the following error message while trying to push my commits upstream:
An internal Exception occurred during push: [URL] git-receive-pack not permitted
For some reason, this happened because I was using https for my checkout. While trying to perhaps switching this with another protocol (ssh), I couldn't find any obvious context menu option to switch the repository access configuration. A little more digging revealed that the solution is sequestered within Context menu, Team, Remote, Configure Push to Upstream. Clicking on the Change button next to the URI field should bring up the familiar repository configuration dialog.
Switching from https to ssh did the trick for me.
I hope this helps!