unspecified launch failure for RadixSort

In my particle-based source code I’m using the source code directly from the particles project to radix sort particles, but I get an unspecified launch failure when I call the RadixSort function.

Any suggestions?

The radix sort code I’m using seems to be written for 32 bit. If I’m using a 64 bit processor do I need to amend the radix sort kernels for 64 bit by replacing 32 with 64?