I have a VPS with Ubuntu 11.04 and I installed PPTPD but is not working correctly, only allows 1 user at time and I need it for more users.
I guess that is a bad configuration and/or a firewall issue. (I don't have enough time to look into it)
I need that fixed and step to step guide of how was it fixed, I have other server with the same issue and need to reproduce the solution.
I will provide SSH access to the winner, the payment will be done using escrow and only will be released when PPTPD is working correctly for multiple users.
Happy Biding. Please ask if you have questions.