VirtualBox+Comodo+Vista VPN

VirtualBox+Comodo+Vista VPN(PPTP) can’t work together.
ping -l 188 pass through VPN right. Bigger packets not
ping -l 189 (for example).

Vista sp1. Comodo Internet Security 3.5 and 3.8 version.

You said you removed VirtualBox and it works again ?
Is the problem system the Host or the Guest system (the one running in VirtualBox ?)
Can you post your VirtualBox version used…

And of course your other system specs needed for bug reporting, see here: