Yes, you are right, I've must have confused it with the official Catalyst tool icon.
In fact, I've downloaded it and, guess what, Couatl crashes on my system too, if the ATI Tray Tools is loaded! We thought to have an easy reproducible case, so I forwarded this to Alberto ( our Couatl developer ) so he could debug it, and he has an ATI card too, although it's an older mobile version, but unfortunately, it works just fine on his system...which means we are still back at square one.
Maybe this tool creates this conflict only on specific ATI cards, I guess not the tweaks are the same for all models. And, while I'm running Windows 7 x64, Alberto still uses old trusty XP, so maybe it's only happening on 64 bit OS or only on Windows 7.
Until we find the cause, the only solution is to do all needed tweaks before launching FSX, then quit the ATI Tray tool.