Open vpn Server problem

Hi, I have the following Scenario.

adsl modem (192.168.1.1)———glinetar750(192.168.8.1 using 192.168.1.2 from adsl)
Dmz to the ar750 to 192.168.1.2

OPEN vpn Server ON ar750.
I am Able to Connect to vpn Server. But I am unable to ping any ip under 192.168.8.x segment.
I am able to reach adsl modem under 192.168.1.1 only.

ideas what is Going no.

You need to enable Access Local Network.

Thanks a lot. I did enable this option and i am able to access the lan.

Still cant access the router ar750 192.168.8.1admin page over the vpn. Do i need to modyfi something else?