Step Input crashses

Hi, I have been playing about with ‘Step Input’ and it keeps crashing. It doesn’t happen all of the time but just crashes out of the blue. I’m pretty sure it’s only when I use Step Input? I have one version of EWQL with one instrument using the Play engine. I don’t have anything else running and the pc is not on line. Out of nowhere I get:

Cubase 6 has stopped working. A problem caused the program to stop working. Windows will close the program and notify you if there is a solution’

Any one have any ideas?