VPN doesn't work with Mac with new Router

Ok, here's an odd one for you.

In the previous setup, we had a Netgear WPN824v2 wireless router. It had port forwarding enabled to the server, which is running Small Business Server 2003. The client who had a MacBook running OSX 10.5.8 had no problems connecting to the network using the Mac's built-in VPN PPTP software.

Since then, their router died and I replaced it with the same model, but version 3 instead of version 2. It has the latest firmware available from Netgear. I made sure all the settings and port forwarding was entered the same, and tested VPN connection with a Windows machine and it connected fine with no problems.

But now, with this new router, the Mac cannot connect to the network using the same exact settings. I tried tweaking everything I could on the settings in the Mac, thinking it was some small detail, but nothing I change makes a difference.

The error message I get on the Mac is "Could not negotiate a connection with the remote PPP server. Please verify your settings and try again."

I have tried using that user's credentials to connect with a Windows machine (running XP, Vista or 7, all work) and it connects with no problems, so it isn't a permissions issue. It -does- work, just not with the Mac.

I tried posting to Microsoft Newsgroups, they said it was a router issue.

I posted to Netgear's forums and they said to call Netgear support. I called them, and after 2 hours of being transferred around and talking to idiots, they told me that it's not the router, since it does work. Well, it only sort of works. What am I supposed to do.. tell clients they can't own a Mac and work from home??

I'm trying to find a solution to actually resolve this problem and help the client, since they have been out of luck for so long. Does anyone know if there's a list of routers that have been tested with VPN on the Mac and therefore know for sure if they work or not? I don't want to replace it with a different router and run into the same problem. It seems like a common enough problem that this list may exist somewhere...

Also was wondering if anyone had any ideas on this, I'm totally stumped.

Any ideas on this? I really need some help.

Even if you just have a suggestion for a different forum to post to, that would be helpful.

Make sure when you enable port forwarding, you enable is as a VPN protocol.

Your Mac could be looking for the old MAC of replaced Netgear - what about deleting Network from MacBook and re joining.

Speaking of VPN protocol when enabling port forwarding, I would just like to share a VPN service from US that will interest you all. This US VPN is actually on of the top in the internet and have been delivering great services and advantages to their customers. It doesn't just give you security for your internet privacy, it also gives you benefits while having their service. Trust me, it's worth to be checked.