I've found a problem trying to upload sketches on Arduino Pro Mini 3,3V with ATmega328, using FTDI Basic Breakout 3,3V. The error is always this one:
System wide configuration file is "C:\Program Files\arduino-0022\hardware/tools/avr/etc/avrdude.conf"
Using Port : \.\COM2 Using Programmer : stk500v1 Overriding Baud Rate : 57600 avrdude: ser_open(): setting dtr avrdude: Send: 0   avrdude: Send: 0   avrdude: Send: 0   avrdude: Recv: avrdude: stk500_getsync(): not in sync: resp=0x00 avrdude: Send: Q   avrdude: Recv: avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51
avrdude done. Thank you
I've tried a lot of things, without success, and using FTDI Basic Breakout 5 V with Arduino Pro Mini 5V everything goes fine very quickly.
What is wrong in 3.3V version? Anything on being particularly carefull in that case?