FIO hangs when XBee plug on

Hello,

I can't get the FIO working when a XBee is plugged on.

A simple led13 blinking (without anything linked to the serial) will work when there is no XBee and will not work with a XBee.

The issue appeared with different xbees (and they are functionnal).

I noted that without the xbee, the ON led is not lighten (while the device is obviously running). With the xbee, it is lighten.

The configuration is standard and I haven't done the configs to enable wireless programming...

Do anyone has an idea what I'm doing wrong?
Thanks!

Well, after some investigation, I found out that if the arduino is powered with the 3v3 FTDI port, it will boot normally and send messages via the XBee...

Would it be a problem with the FIO 3v3 regulator?