I keep getting this Fatal Error message, Help!

Im trying to update software on my Makergear M2 for my dual extruders. I downloaded the needed marlin software but when I put it in my sketch.I get this message.

Arduino: 1.6.4 (Mac OS X), Board: "Arduino Mega ADK"

Marlin.pde:33:27: fatal error: Configuration.h: No such file or directory
compilation terminated.
Error compiling.

This report would have more information with
"Show verbose output during compilation"
enabled in File > Preferences.

Thanks

The Configuration.h file containing the settings specific to your device should be in the same folder as your Marlin firmware.

Your version of Marlin is quite old. The newer versions use Marlin.ino, not Marlin.pde. You should look into getting a recent version. https://github.com/MarlinFirmware/Marlin