Arduino Fio - problem uploading sketches and with serial monitor

Hi everyone,

I've started using arduino in order to instrument some stuff. I've started with a UNO, and tested all sensors and a Xbee there, but since weight was a constraint I planned on using the FIO.

More often than not I get the following error while uploading any sketch to the FIO:

Arduino: 1.6.5 (Windows 8.1), Board: "Arduino Fio"

Sketch uses 7,602 bytes (24%) of program storage space. Maximum is 30,720 bytes.

Global variables use 483 bytes (23%) of dynamic memory, leaving 1,565 bytes for local variables. Maximum is 2,048 bytes.

avrdude: stk500_paged_write(): (a) protocol error, expect=0x14, resp=0x00

avrdude: stk500_cmd(): programmer is out of sync

Problem uploading to board. See for suggestions.

This report would have more information with
"Show verbose output during compilation"
enabled in File > Preferences.

This occurs with more frequence for bigger files, and less so if it's the first upload after starting the Arduino program.

Additionally, if I manage to upload the sketch, the serial monitor stops updating some time (10-20 s) after the start, I've also used another serial monitor (TeraTerm) which also stop updating, so I figure it's something with the ports.

I'm using the sparkfum 3.3V FTDI Basic breakout, the PC is running Windows 10 not 8.1 as stated in the error message. The sensors I've been testing are the Altimu-10 v4 and Ultimate GPS Breakout V3.

If I'm leaving out some useful information please say so and I will post it.

I appreciate any help, and thank you all for your time.