http://www.canfield.com/content/openvz-unable-open-pty-no-such-file-or-d... has a post to the problem on the error message

Unable to open pty: No such file or directory

Quote:

The fix then becomes a two step process. The first steps are done from the node, adjust your vz container ID from 101 as needed. Re-create the missing devices.

sudo vzctl exec  101 /sbin/MAKEDEV tty
sudo vzctl exec 101 /sbin/MAKEDEV pty

You should be able to log in via ssh or vzctl enter BUT the problem may re-appear on an update (yum update). The next steps should help with that. Enter the container and edit the file /etc/rc.sysinit. Search for the line /sbin/start_udev and replace it with the following. This disabled udev without removing the package and auto-repairs the devices if by some chance they go missing again.

# udev mucks up OpenVZ - disable it and auto-fix it if it goes bad again
#/sbin/start_udev
/sbin/MAKEDEV tty
/sbin/MAKEDEV pty