I got an esplora recently, and after much hassle with drivers, managed to upload some sketches with a windows 7 laptop. Today, I pulled it out, and tried to upload a sketch with a laptop running 64-bit fedora 17 I got this in my verbose output:
avrdude: Send: S  avrdude: ser_recv(): programmer is not responding avrdude: butterfly_recv(): programmer is not responding
I also tried again with the windows laptop. Sometimes I got the same error, sometimes arduino couldn't find the Esplora.