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

Ext.ux.grid has no properties
...
Line 141

Solution
In Heroku, you will probably have to manually upload the files from the ExtJS library, as well as the ext_scaffold plugin.
When you do that, two files that ext_scaffold needs, and which they should be located in ext_scaffold/assets/javascripts should be copied to public/javascripts.
The files are:

ext_datetime.js
ext_searchfield.js