There was already a thread about this issue. I've copied one line out the Mac thread:
Probier mal folgenden <a href="
http://www.partout.info/brettspielwelt.dmg" target="_blank">Client[/url] aus.
It points to a client with the start program in universal binary. This worked on my MacPro. If the start program needs Rosetta, the whole client will run in that environment, which is slow.
Best regards
wla