error: Can't lock ref

Hi folks,

I've just pushed up a packed git repo:

http://www.kerneltools.org/pub/downloads/module-init-tools/devel/module-init-tools.git

Attempting to clone this repo using http generates the error in 
$subject. Brief searching via Google suggests this is an appache 
permissions problem - anyone got a trivially obvious apache config fix 
before I go trawling through to figure out what's up?