Prusa i3 Pro C extruder issue

[newman13f]

Good day everyone. Recently I've run into an issue with my dual extruder prusa. After calibrating my machine, neither of the extruder motors are turning whatsoever. I'm running on repetier host, and using Slic3r as my slicing program. I've attempted many times to run the printer through a project and its hasn't been extruding any filament at all. I've taken the motor plugs for the extruder steppers and switched them with an x or y axis plug and the motors turn fine. I'm glad to know that my motors aren't burned out or anything like that. Would anyone happen to know what's going on? It's so frustrating. Thank's in advance!

[Mark]

What's the temperature of your extruder? the motor won't turn until it reaches 170℃.

[newman13f]

I have it set to 230 for ABS. This problem happens even when the extruders are at 230 degrees.
I have looked on the forums and noticed a lot of people are having the same issue. My apologies for the redundancy.
From what I've read on other threads, I will have to reinstall marlin onto my GT2560. Unfortunately I have not been able to figure that out.
The computer I'm using is a macbook pro. I have already installed Arduino onto my computer, and opened Marlin firmware that I got off a link for the i3 Pro C dual extruder. After checking through all the presets seeing that they should all be fine, I clicked confirm and got some error code that I cannot decipher.
Could anyone send me a link to a tutorial for mac on how to install Marlin firmware onto my GT2560?
Thank you.

[Mark]

"got some error code that I cannot decipher"
What's the error? can you post a pic here? And did you connect 2560 to your mac successfully?
Here is the link to this :http://www.geeetech.com/wiki/index.php/ ... _Mendel_I3