title: Error pushing to GitHub - insufficient permission for adding an object to repository database
body: <p>I'm getting back an unusual error while trying to do a "git push" to my GitHub repository:</p>
  
  <pre>
  Counting objects: 8, done.
  Delta compression using 2 threads.
  Compressing objects: 100% (4/4), done.
  Writing objects: 100% (5/5), 1.37 KiB, done.
  Total 5 (delta 2), reused 0 (delta 0)
  error: insufficient permission for adding an object to repository database ./objects
  
  fatal: failed to write object
  error: unpack-objects exited with error code 128
  error: unpack failed: unpack-objects abnormal exit
  To git@github.com:bixo/bixo.git
   ! [remote rejected] master -> master (n/a (unpacker error))
  error: failed to push some refs to 'git@github.com:bixo/bixo.git'
  </pre>
  
  <ul>
  <li>After a clean clone from GitHub, I can edit/add/commit/push a modified file.</li>
  <li>If I then repeat this a second time I get the above error.</li>
  <li>I can push to other GitHub repositories just fine.</li>
  <li>I've checked file/directory permissions on my side, and they seem OK.</li>
  <li>I'm running git 1.6.2.3 on Mac OS X 10.5.8</li>
  </ul>
  
  <p>The above repository was the source of my fun for a previous Stack Overflow question (<a href="https://stackoverflow.com/questions/1904860/how-to-remove-unreferenced-blobs-from-my-git-repo">SO 1904860</a>), so maybe the GitHub repo got corrupted. The only similar issue I've found via searching was an <a href="http://support.github.com/discussions/repos/791-error-unpack-failed-unpacker-exited-with-error-code" rel="noreferrer">unpack failed</a> problem reported on github. Has anybody else run into this issue before, especially when <em>not</em> using GitHub?</p>