Firefox/Seamonkey/IceCat and the "Couldn't load XPCOM" error

So I ran into this error upon installing Seamonkey v2.29 in order to do some compatibility testing. This was particularly annoying because I have a version of Firefox that is running just fine.

I had downloaded the Seamonkey 64-bit contributed build, and untarred/bzipped in my /usr/lib64 directory and then attempted to launch, only to see the dreaded:
Couldn't load XPCOM.

A search on the web lead to many suggestions of re-installing, which I considered to be using a machete when a scalpel should suffice.

So a little more digging suggested the problem is the ability of the program to link with the correct version of xulrunner. The seamonkey subdir does contain its own libxul.so and run-mozilla.sh, but apparently those are not interfacing with the rest of the system well.

So a peek inside /usr/lib64/xulrunner showed that it, too has a version of run-mozilla.sh. So I simply executed:
$ /usr/lib64/xulrunner/run-mozilla.sh /usr/lib64/seamonkey/seamonkey

and problem solved.

This, I'm sure, is an entirely unsophisticated description and understanding of what's going on, but the solution works (at least for me on my system).