I don't really like that route notation for a normal Ethernet. Try changing:
ip route 10.0.0.0 255.0.0.0 FastEthernet8
to have a proper next hop of:
ip route 10.0.0.0 255.0.0.0 10.1.36.125
Is FastEthernet8 definitely up?
The other thought going through my mind is their is already a translation entry in the cache. Try doing a:
clear ip nat ranslation *