The official EXIFtool installer indicates that it places the binary in /usr/bin not /usr/local/bin:
http://www.sno.phy.queensu.ca/~phil/exiftool/install.html#OSX
I use EXIFtool as installed by MacPorts, so my copy is located in /opt/local/bin .
Will SetEXIFData work with that out of the box, or do I need to make a symbolic link in /usr/local/bin to the actual binary?