This is a 500 pointer guys....
I've got a Windows 2003 PPTP VPN setup, and everyone connects to it perfectly.....besides my boss. He still uses dialup, and he connects to the vpn fast, but after he connects, and he tries going somewhere his isp (dialup) kicks him off the net. He's the only one that uses dialup, thats uses the vpn. He has no problems what so ever just browsing the internet and stuff like that, the only time it drops on him is when he connects to the vpn.
He hasn't sucessfully gone to any sites that in our intranet or anything, when he tries it drops.
He's using Windows XP Pro.