This sounds like a problem you had earlier – basically loading the program crashes the DSP. It's usually fixable by holding down the PROGRAM key at startup, but this obviously does not resolve the underlying problem.
There are a number of possible causes:
1) Failed update leaving mismatched software.
2) Hardware problem of some kind – if it happens again, take the top off the unit and "wiggle" all socketed parts and connections in case there is a bad contact somewhere. Especially U106.
3) Software bug. In this case it would probably be repeatable and maybe only apply to certain programs.
4) Unstable clock source when using digital input.
5) Overheating due to insufficient cool airspace around unit.
If the above doesn't help, we could run some selftests. Hold down the 1 key at the first startup screen, and release it when asked. Turn the wheel until it shows "(053) Test DSP #0,1". Hit select. Let this run for a few hours. The P number will increment. If either the E= or the T= show other than 0, let me know.