I have mounted a geeetech pro b, and I can't connect to my pc. I've installed repetier-host, intalled arduino 1.0.1, 1.0.6, 1.8.0 and configure the board 2560, Port (com3) and baud rate (230400, I have tried others). But when I try to upload the marlin firmware (geeetech firmware from here http://www.geeetech.com/forum/viewtopic ... 10&t=17046 and directly downloaded from marlin web) to the i3 pro b, it say error, the message depens on the Arduino version.
For example in my actual installed version (1.0.6) when I try to upload, arduino say me:

I have modified all marlin firmware tried like here say ( http://www.geeetech.com/forum/viewtopic ... 13&t=17194 )
configured de usb serial port (com3) with 230400 baud rate

in the repetier-host too

And always time when I try to conect repetier-host it say me this:

I have tried this with two diferent pcs.
Help please!