WFP fails to run on 64-bit Linux | similar but different

Forum: Wordfast support
Topic: WFP fails to run on 64-bit Linux
Poster: Anthony Baldwin
Post title: similar but different

I downloaded the WFPro demo for gnu/linux, on a Debian 7 Wheezy system,
AMD64 architecture.

I can not get it to run.
I get

$ ./Wordfast
./Wordfast: error while loading shared libraries: libgtk-x11-2.0.so.0:
cannot open shared object file: No such file or directory

But that library IS installed!

$ locate libgtk-x11-2.0.so.0
/usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so

Right where it should be and always is.
I have the ia32-libs installed, which I understand are needed.