Librarian-puppet package seems to get into an infinite loop

I've just started looking into librarian-puppet on CentOS 6, Ruby 1.8.7, and it appears that when running librarian-puppet package it gets into an infinite loop when fetching from puppetforge. I'm fairly new to ruby, but the bit of code it seems to be tripping up on is in lib/librarian/puppet/source/forge.rb, in the vendor_cache function. The while loop which loops over input.read never finishes, as it would seem that without a length argument it returns the whole file each time. This only happens when calling package, install works fine.