Actually, you've isolated the cause correctly - you don't have the pix properly configured for a translation for this subnet.
You need to be a little more specific about your nat statement for us to be sure that it's correct. Also, that nat statement has to map to a global (assuming that you are actually nat'ing) on the outbound interface.
i.e. If you are going to 198.133.219.25, then whatever interface the pix thinks that network can be found (default route to the outside, for instance), then you need a matching global for your internal nat.
i.e. something like:
nat (inside) 1 10.1.64.0 255.255.224.0
global (outside) 1
route outside 0.0.0.0 0.0.0.0
Make sure that the host that doesn't have a translation actually falls within the remote network/subnet mask you've specified (10.1.64.0 - 10.1.95.255).
HTH
Jeff