I can no longer run programs on a LPC1768 that were downloaded from a Mac. The same project works fine when using a PC. I am using the same chip for both system.
I have tried two different LPC1768 chips
I assume that you have installed Keil MDK.
The supported Operating System is Windows, but not Mac OS or Linux, see:
System Requirements (keil.com)
GENERAL: Keil MDK 5 on a Mac (arm.com)