I have a small Ubuntu 9.04 router setup as a NAT box and a PPTP server. After a power failure everything except the PPTP server still works. A windows client gets to "registering your computer on the network" but then says

Error 742: The remote computer does not support the required data encryption type.

I did some research and I think the problem is with the ppp_mppe module. When I try to run 'modprobe ppp_mppe' it hangs indefinitely.

What would cause this hang? Any ideas how I can troubleshoot this further?

Thanks for the help!

UPDATE: I am still having the problem, however I have found some more information.

When the first user tries to connect to pptp, the process list shows modprobe sha1 running, and one instance of modprobe ppp_mppe for each connection attempt. If I killall modprobe at this point the next connection attempt works, and everything is fine until the next reboot. I'm planning to do a clean install at some point in the future but I'd really like to get to the real cause of this.