Problem
Trying to use the heroku gem to clone a project and do local modifications I got the following error:

git: fatal error: `chdir' failed: permission denied.

Solution
It turns out that in Mandriva, when using:

sudo urpmi git

what gets installed is the ‘GNU Interactive Tools’ that has nothing to do with the git version control system.
So make sure you first uninstall the git installed:

sudo rpm -e git

and then install the Git – Fast version control system, by doing:

sudo urpmi git-core

You should then be able to clone a heroku application:

heroku clone myapp