Can't connect VPN server with encryption
 

I'm using rh 9.0 and pptpd-1.1.3-4.i386.rpm
but when i use window client to connect linux VPN server. It is a problem
because it is a encryption problem. When i don't use encryption, winodw
client can connect to VPN server

How can i do connect VPN server with encryption?

Help me please

I'm a new also in VPN that is also my problem. When i try to connect to the VPN server using Win Xp client with encryption. I can't connect to the server. But when i remove the encryption it all goes well. But isn't it that without encryption VPN server is less secure. How to configure the server in a way that it can accept window client with ecryption.