I'm playing on a Mac and I don't use the island rum launcher, I just made a shortcut straight from the COH application itself and it works like a charm. Here's the steps to do this:
1. Open up your drive
2. Open the Applications folder
3. "Drag" the COH icon to the desktop to create a shortcut
4. Use that to launch the game and use your game login
I get zero crashes and the game runs smooth.