poptop pptpd cant ping local ips

i can connect to my vpn server, i set up the server with one ip
i assigns 10.0.1.20-22 and it allows browsing of 10.0.1.2-12
the ip of the vpn is 10.0.1.9
i connect to the vpn from my dlink router i map the vpn ports
to the linux vpn server.
i also tried connecting setting up an alias as 10.1.1.9 and connection
to the alias and assigning 10.0.1.20-22 to the vpn client. i got the same
result. i setup this alias so i dont have to connect through the internet
to ignore address in the same hub.
i can ping the server 10.0.1.9 but i cant ping 10.0.1.3 (another box)
do i need an ip tables rule to do this? what rule? can it be just for
address 10.0.1.2 to 12. ?
do i need two interfaces?
do i need to assing 10.1.1.X address to the vpns clients? or can i just use
one interface?

i have slackware 9.1 2.4.23 and have the pptp 128 bit kernel patch. and i
get connecte with mutual chalenge authenticatin and strong microsoft
encryption. i dont think the patch or the connection settings have anyting
to do with this error but just in case someone asks.
I got the patch from here
http://www.polbox.com/h/hs001/
my kernel also has a freeswan patch.

Thanks.