[Lazarus] Debugger Error: "PC register is not available"

[John Repucci]

I just encountered the below pop-up error message when debugging.

Within that one session of Laz, I was able to reproduce the message,
but once I existed / restarted Lazarus, it did not reoccur.

Any suggestions for the next time I encounter it?

code segment:  sA,sB are strings; I was able to step past the sA line
and sA evaluated correctly.  Every time I attempted to step over the
sB line, I received the error.
  sA := KeyStrings.Strings[0];
  sB := KeyStrings.Strings[1];

---------------------------
Debugger Error
The debugger encountered an error when trying to run/step the application:
PC register is not available
Press "OK" .... [etc ...]
The more button gives ",msg="PC register is not available""
---------------------------

Laz: 0.9.31-35589, 2.6.1, win32, running on a Win7-64 bit system.