Geeetech Kossel Delta Firmware

[ChrisP28]

I have built from kit form a Geeetech Kossel Delta Rostock G2S Dual Extruder 3D printer. A friend has loaded a basic Firmware and we have checked the build works within the limits of the firmware loaded. It homes the heads and turns on the heated bed and extruders and tries to carry out the bed leveling function. I'm reasonably sure the build is OK and the board, a GT2560, is communicating and working.
My problem is the Firmware. I have followed the instructions in the manual. Downloaded the Arduino software and the Marlin Firmware. I have followed the instructions to start the Marlin.ino file and it opens the Arduino but with no Tabs. I have followed the instructions on this forum and followed the links to the various places to access the firmware for my board/printer but it seems to bounce me backwards and forwards to the same pages without leading me to the firmware. I have found versions of the firmware which I have opened in Arduino but they refuse to compile and therefor won't upload to my machine. I get error messages referring to fpos and position references.
My laptop is running Windows 8 which I hate. Is this a problem should I use a windows 7 O/S? I have also tried it on my Mac with no better results.
I have approached the Geeetech technical help but they have referred me back to this forum and the links which, as I have already mentioned, did not help me. I have no C++ programming experience and at the time of purchase I didn't realize the firmware would be such a problem. I had expected a Plug-and-Play set up with some tweeks for calibration.
Is there someone out there that could help me with a copy of the firmware that works and compiles and idiot instructions as to which operating system and versions of software I need to get my printer working.
Many thanks for any help you can offer.
ChrisP28

[William]

You should upload it via Arduino 1.0.1