I'm surprised that it doesn't work when you use the watchdog timer.  Can you provide more details (e.g. a sample sketch and the behavior you see)?

On the other hand, a "jmp 0" might not work, because it doesn't necessarily shutdown / re-initialize the registers / peripherals / USB connections.  On the Uno, the USB-serial connection is done by a separate chip, so you the connection will stay up regardless of what you do to the main processor (ATmega328).  On the Leonardo, there's just one chip, so you have to be more careful about maintaining the USB connection.

It sounds like there may be different things going on here, since some of you are seeing different symptoms / behaviors. 

Josephiah and DROBNJAK, can you post the verbose output of an upload attempt?  Have you tried a different USB cable?  Are you going through a USB hub (if so, try connecting the board straight to the computer)?

Weird.  Where was the old eeprom.h file located?  Where did you get the one you replaced it with?

For those of you having trouble, can you try changing "stk500v2" to "wiring" for the Mega 2560 in your boards.txt file (in the hardware/arduino sub-directory of your Arduino application directory)?  That should tell avrdude to do an auto-reset of the board before the upload (in addition to the one done by the IDE itself), which might help.

See: http://code.google.com/p/arduino/issues/detail?id=806 for more information and updates.

Unfortunately, we can't really support other people's products, since we don't know the details of how they're designed or what software they're running.  I recommend you ask Seeedstudio for help.

You might try running Arduino by invoking java from the command line, as this should print the exception, if any, that's being thrown.  I think you can run "arduino.exe --l4j-debug" to get the right command line. 

Weird, it works just fine for me with Arduino 1.0.1 (on Windows with the Mega 2560 or ADK selected).  I don't think it's changed since 1.0).  Can you post your sketch?

In Arduino 1.0 and later, you can get verbose output by checking a box in the preferences dialog (holding "shift" uploads via an external programmer, which is why it gives you a different error).  Can you post the output from that?

Do you have any bluetooth scanning / communication programs running (maybe in the background) or software for a cellular internet dongle or anything else that might be grabbing USB ports?

Try this, from the Leonardo getting started page (http://arduino.cc/en/Guide/ArduinoLeonardo):

These differences affect the way you use the physical reset button to perform an upload if the auto-reset isn't working. Press and hold the reset button on the Leonardo, then hit the upload button in the Arduino software. Only release the reset button after you see the message "Uploading..." appear in the software's status bar. When you do so, the bootloader will start, creating a new virtual (CDC) serial port on the computer. The software will see that port appear and perform the upload using it. Again, this is only necessary if the normal upload process (i.e. just pressing the uploading button) doesn't work. (Note that the auto-reset is initiated when the computer opens the Leonardo's serial port at 1200 baud and then closes it; this won't work if something interferes with the board's USB communication - e.g. disabling interrupts.)

Weird.  Can you try going into your boards.txt file (in the Contents/Resources/Java/hardware/arduino sub-directory of the application) and changing "stk500v2" (for the Mega 2560) to "wiring"?  That should tell avrdude to reset the board before upload (in addition to the reset that's done in the IDE) and might help.

Weird, I thought I fixed this a long time ago: http://code.google.com/p/arduino/issues/detail?id=381

It seems to work on my Mac.  Does this happen for everyone on Windows?

Hmm, it shouldn't matter what code you're trying to upload.  Does it happen only if that sketch is already on the board (i.e. can you upload it once)?  Does it fail for other sketches (without the goto)?

Can you post your sketch?

matinzk and hpt007: unfortunately, we can't provide support for non-Arduino boards as it's impossible to know exactly how they're designed / what software they're running / etc.  I'd suggest asking the maker of your board for help.

I haven't seen this, but I wonder if it's a line-ending issue.  Maybe try deleting all the line endings and then re-inserting them? 

Also, do you have anything in the hardware sub-directory of your sketchbook?  It's possible that a boards.txt file there is somehow interfering with the one that comes with the software.