Sounds like you have two subnets on your inside network. If this is the case you will need to specifiy in the pix a default route to get to the remote subnet. Is there a router before the pix on the inside of your network? (router-pix-internet). If there is then the route should point to the interface that is directly connected to the pix.
Also in the router you should have routes defined to get to your other subnets. Hope this helps.