I'm getting the error message that the system is not able to locate the package kamailio.
I navigated the repo on that site and I can see that there is a kamailio package, but it's located under http://repo.pouf.org/raspbian/pool/main/k/ folder.
I've also tried to change the sources.list file to read:
deb http://repo.pouf.org/raspbian/dists/ wheezy main
But that didn't fix the issue.