If I am correct you are trying to pass traffic from an inside host to an outside host through your pix, yes? And you are trying to ping the outside intf of the pix from a host on the inside.
You cannot ping an interface of the pix from a host unless you are directly attached to that interface or coming from a segment that is on the same side as that interface. That is why from inside the pix you can ping all the interfaces and from your inside host you cannot ping the outside intf.
Since you are only using two interfaces, your basic config to allow traffic should include a nat and global entry to allow your inside hosts to go out. If you need to allow outside hosts in, you need static and conduit. Perhaps you have done all this already.
good luck
gilles
