Got a project set up in Eclipse, feeding into Bitbucket through eGit. Been going for 6+ months now.
Pushed a commit in this morning on machine 1. Worked fine.
Pulled it down on machine 2. Worked fine.
Updated some code on machine 2.
Pushed a commit up - and it failed.
It was failing with a 405 Service Not Allowed, but after rebooting my machine it's not failing with a service=git-receive-pack not found.
I'm assuming this is your end as I've not changed anything my end...