Hi, i love your 737, and i am using it in xp with ninja tricks. I know what to expect and not expect, so this report, is only a helping hand, for you to get it ready for xp11.
I dont know if you can use it to anything, if not, just throw it away.
I got the fault in the screenshoft after:
1. resetting FPL in flight by entering a new origin airport.
2. setting MCP to a lower alltitude.
3. Trying to enable LNAV
Other than the errormessage, i also experienced that i could not press "EXEC", nothing happened, and "EXEC" kept lighting up.
Hope you can use it.
best regards
Thomas
edit: forgot to mention, im using xp11 ver. 11.02r1