Wow Wont Open On My Mac?

I have a mac OSX something or other, i believe its a 1,4 or 1.3 tiger version, I had Just World Of WarCraft (WOW) installed, and it opened worked fine, then i installed the expansion, upgraded my account, and then tried to open WoW and bam, nothing! It bounces and then nothing at all, not a pin wheel moving nothing. I’ve also tried waiting and giving it time, still nothing. Please Help!!!