Unknown huh?

I got these error messages from the Gcode_interpreter (one advantage of ReplicatorG over the Java Host is that it shows messages from the firmware):

Estimating build time...
Estimated build time is: 13 minutes
Running GCode...
Running warmup commands.
Unknown: E: 151
Running build.
Unknown: huh? G669
Unknown:
Unknown: E: 151
Unknown: huh? G669
Unknown:
Unknown: huh? G669

Checked the code to find that E: indicates a temperature error. Recompiled and ran the Gcode_interpreter in testmode to discover that my own adjustments for the extruder and motor settings conflicted with the EXTRUDER_0_TEMPERATURE_PIN. Now the temperature test reads plausible temperatures and the heater goes hot and cools down.