Unable to upload sketch to Leonardo I'm really at my wits end. For a couple of hours I have been programming a custom board that uses everything as on the Arduino Leonardo. A few hours ago I am not able to upload anymore.

I get the following error:

   avrdude: error: buffered memory access not supported. 
   Maybe it isn't a butterfly/AVR109 but a AVR910 device?


I've tried everything from re-installing the IDE, re-installing the board in Device Manager, changing the COM Port. I really just don't know anymore.

Here is some more data that might be relevant or useful:

     Using Port                     :\\.\COM6 
     Using Programmer              : avr109
     Overriding Baud Rate          : 57600
     AVR Part                      : ATmega32U4
     Chip Erase delay              : 9000 us
     PAGEL                         : PD7
     BS2                           : PA0
     RESET disposition             : dedicated
     RETRY pulse                   : SCK
     serial program mode           : yes
     parallel program mode         : yes
     Timeout                       : 200
     StabDelay                     : 100
     CmdexeDelay                   : 25
     SyncLoops                     : 32
     ByteDelay                     : 0
     PollIndex                     : 3
     PollValue                     : 0x53


[EDIT]
I've now checked the battery (yes with a multimeter), it is fully charged, as it charges when the USB is connected. I've also tried a different computer, along with a different USB cable.
Try this:

First: you must find the COMx used for your "Arduino Leonardo" in the "Device Manager" of Windows.

Second: make double click to see the properties of the device, and go to the "Port configuration tab"

Third: enter in "Avanced Options" and deactivate "Use FIFO buffers", and accept all changes.