:: What is PPTP
The Point-to-Point Tunneling Protocol is a method for implementing virtual private networks. – WikiPedia
 
:: Load modules on OpenVZ Server

modprobe tun
modprobe ppp-compress-18
modprobe ppp_mppe
modprobe ppp_deflate
modprobe ppp_async
modprobe pppoatm
modprobe ppp_generic

 
:: Setup OpenVZ Container for PPTP

vzctl stop ID
vzctl set ID --features ppp:on --save
vzctl start ID
vzctl set ID --devices c:108:0:rw --save
vzctl exec ID mknod /dev/ppp c 108 0
vzctl exec ID chmod 600 /dev/ppp

* ID = VPS ID (vzlist)
Now, you can install and configure PPTPd in your VPS.
 
:: Link
+ Google
+ WebHostRepo