I have a Mac. I meet all the prerequisites. BUT. . .

This is something that has been giving me trouble on Dungeons and Dragons Online - and now here for LOTR. When I launch the game it works perfectly, until it reaches "checking dat files." Then no matter how long I let it sit it doesn't change. Several times I have left it until my computer finally gave up and said that the application was not responding.

I'm redownloading, but i've done it before and it didn't work the last two times.

Any ideas?