Addenda

[Isaac Yonemoto]

I also found it helpful to add the following line to my fstab:

tempfs  /dev/shm  tmpfs   defaults        0  0

And I also removed from

.../Mathematica/6.0/SystemFiles/Autoload/PacletManager/PacletManager.m

all lines between

BeginPackage["PacletManager`"]

and

EndPackage[]

This is beacuse Java does not work so hot on my machine.

Now Mathematica works great.

Thanks

Isaac