Hi,
There is indeed a bug with some Macs for the trial. We will release a version with a fix tomorrow or monday.
For your information, Mac OS X sometimes returns a null value for some pieces of Hardware we are checking in order to create the license file, hence the problem...
If you don't wait for the fix, please use the trial license I am enclosing here, which will work up to Marche 12th. You can install it on as many computers as you want as long as they are not on the same subnetwork.
Cheers,
Nicolas