Fatal error: Uncaught exception 'Exception' with message 'error: unable to unlink

[vivek0460]

I have setup Git pull from web with this library and when i am trying to pull in server its says

Fatal error: Uncaught exception 'Exception' with message 'error: unable to unlink old 'xxxx.file' (Permission denied) fatal: Could not reset index file to revision 'FETCH_HEAD'. ' in Git.php:317 Stack trace: #0 Git.php(332): GitRepo->run_command('/usr/bin/git re...') #1 filename: GitRepo->run('reset --hard FE...') #2 filename(30): RunGit->doPull() #3 {main} thrown in Git.php on line 317