Upload to 2560 and/or Uno works on one OS X machine, but not the other

The board is recognized as /dev/cu.usbmodem621 and /dev/tty.usbmodem621. Sketches compile okay. When I try to upload, I get:

java.lang.NullPointerException at processing.app.debug.AvrdudeUploader.getProgrammerCommands(AvrdudeUploader.java:106) at processing.app.debug.AvrdudeUploader.uploadUsingPreferences(AvrdudeUploader.java:68) at processing.app.Sketch.upload(Sketch.java:1603) at processing.app.Sketch.exportApplet(Sketch.java:1568) at processing.app.Sketch.exportApplet(Sketch.java:1524) at processing.app.Editor$DefaultExportHandler.run(Editor.java:2293) at java.lang.Thread.run(Thread.java:680)

If upload the digitalReadSerial example using "the good OS X machine" and then plug the board into "the problem OS X machine", I can see the appropriate 1's and 0's go by in the Arduino 0022 Serial Monitor, so the serial driver isn't totally messed up.

"Problem machine" OS X 10.6.7 java version "1.6.0_24" Java(TM) SE Runtime Environment (build 1.6.0_24-b07-334-10M3326) Java HotSpot(TM) Client VM (build 19.1-b02-334, mixed mode)

"Good machine" OS X 10.5.8 Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_28-b04-382-9M3326) Java HotSpot(TM) Client VM (build 1.5.0_28-157, mixed mode)

Stuff I've tried: Reading the troubleshooting guide. changing the java load order from 64bit 1st to 32bit 1st. uninstalling and reinstalling Arduino 0022 Setting the Arduino.app to open using rosetta (32 bit was not an option) temporarily removing /Library/Java/Extensions/librxtxSerial.jnilib other boards, other cables, other usb ports, other machines (other machines did work, but unfortunately, I only have temporary access to the "good machine"

Any suggestions?

Thanks, -Dave

It sounds like there's a problem with one of your configuration files.

You might try deleting your Arduino preferences.txt file (you can find its location in the preferences dialog in the Arduino software). Delete the file when Arduino is not running (or the software will resave the current preferences on exit). The file will be regenerated from its defaults the next time you start the Arduino software. Also, you might try redownloading and installing the Arduino software.

That was it! Mellis, if you are ever in central Florida, I owe you a beverage.

Thanks!!!