Thanks for the insight, Anthony. I think since you have actually experienced it, I feel better answered.
I had suspected latency to be an issue and also read somewhere that VPN works best on a low latency and high bandwidth connection due to its security handshake process.
I gave up after attempting several times during my 2 days in Zim.
The ADSL connection is claimed to be 256kbps for basic($30). I imagine with the better packages, I wouldve had a better chance.
I would mark yours as an answer.