triggering pack-refs

Hi

I was doing push/pull to a remote repo and I suddenly got

Total 0 (delta 0), reused 0 (delta 0)
Auto packing the repository for optimum performance.
fatal: Unable to create 'PATH/packed-refs.lock': Permission denied
error: failed to run pack-refs
To user@hostname:PATH
    abc1..abc2  dev -> dev

Indeed, the group of the user I was using didn't have the permission to 
write in PATH/ . It also seems that git pack-refs wasn't running before 
when I was going push/pull.

My question: is it normal for git pack-refs to be triggered during a 
push for the first time at some point in time (because a threshold of 
something was exceeded), or is this an indication that something else 
might be wrong?

I can post more information if needed. The client is 1.7.0.4 on ubuntu, 
and the git on the server is the same too (I don't know how to see the 
the "git version of the remote repo" - if there is such thing).

Regards
Vangelis Katsikaros