Errors trying to compile FiveD_Gcode_ int

HI, I am new to the community, and very excited to get my Prusa Mendel running. I am using an arduino Mega for the motherboard and a RAMPS 1.4 controller. I have downloaded the firmware for the arduino, changed configuration.h.dist to configuration.h but when I try to compile I get about 50 errors, any ideas about what I am doing wrong? Here are the error messages:

FiveD_GCode_Interpreter.ino:4:22: error: WProgram.h: No such file or directory
In file included from FiveD_GCode_Interpreter.ino:8:
/pins.h:150:2: error: #error Oops! Make sure you have 'Arduino Mega' selected from the 'Tools -> Boards' menu.
In file included from FiveD_GCode_Interpreter.ino:5:
/vectors.h: In function 'FloatPoint fabsv(const FloatPoint&)':
vectors.h:60: error: 'fabs' was not declared in this scope
In file included from FiveD_GCode_Interpreter.ino:9:
/extruder.h: At global scope:
extruder.h:13: error: variable or field 'newExtruder' declared void
extruder.h:13: error: 'byte' was not declared in this scope
extruder.h:390: error: 'byte' does not name a type
extruder.h:396: error: expected `)' before 'hp'
extruder.h:414: error: expected `)' before 'step'
extruder.h:418: error: 'byte' has not been declared
extruder.h:458: error: 'byte' does not name a type
extruder.h:465: error: 'byte' does not name a type
extruder.h:482: error: 'byte' does not name a type
In file included from FiveD_GCode_Interpreter.ino:10:
cartesian_dda.h:69: error: 'byte' has not been declared
/cartesian_dda.h: In member function 'void cartesian_dda::do_x_step()':
cartesian_dda.h:128: error: 'byte' was not declared in this scope
cartesian_dda.h:128: error: 'HIGH' was not declared in this scope
cartesian_dda.h:128: error: 'digitalWrite' was not declared in this scope
cartesian_dda.h:130: error: expected `)' before numeric constant
cartesian_dda.h:130: error: 'LOW' was not declared in this scope
/cartesian_dda.h: In member function 'void cartesian_dda::do_y_step()':
cartesian_dda.h:135: error: 'byte' was not declared in this scope
cartesian_dda.h:135: error: 'HIGH' was not declared in this scope
cartesian_dda.h:135: error: 'digitalWrite' was not declared in this scope
cartesian_dda.h:137: error: expected `)' before numeric constant
cartesian_dda.h:137: error: 'LOW' was not declared in this scope
/cartesian_dda.h: In member function 'void cartesian_dda::do_z_step()':
cartesian_dda.h:142: error: 'byte' was not declared in this scope
cartesian_dda.h:142: error: 'HIGH' was not declared in this scope
cartesian_dda.h:142: error: 'digitalWrite' was not declared in this scope
cartesian_dda.h:144: error: expected `)' before numeric constant
cartesian_dda.h:144: error: 'LOW' was not declared in this scope
/cartesian_dda.h: In member function 'void cartesian_dda::do_e_step()':
cartesian_dda.h:149: error: 'extruder_in_use' was not declared in this scope
/cartesian_dda.h: At global scope:
cartesian_dda.h:163: error: 'cartesian_dda::read_switch' declared as an 'inline' variable
cartesian_dda.h:163: error: 'bool cartesian_dda::read_switch' is not a static member of 'class cartesian_dda'
cartesian_dda.h:163: error: 'byte' was not declared in this scope
cartesian_dda.h:163: error: expected primary-expression before 'bool'
cartesian_dda.h:163: error: initializer expression list treated as compound expression
cartesian_dda.h:164: error: expected ',' or ';' before '{' token
In file included from C:\Program Files (x86)\Arduino\hardware\arduino\cores\arduino/Arduino.h:6,
from FiveD_GCode_Interpreter.ino:41:
c:/program files (x86)/arduino/hardware/tools/avr/lib/gcc/../../avr/include/math.h:439: error: expected unqualified-id before 'double'
c:/program files (x86)/arduino/hardware/tools/avr/lib/gcc/../../avr/include/math.h:439: error: expected `)' before 'double'
c:/program files (x86)/arduino/hardware/tools/avr/lib/gcc/../../avr/include/math.h:439: error: expected `)' before 'double'
FiveD_GCode_Interpreter:90: error: no matching function for call to 'extruder::extruder(byte, byte, byte, byte, byte, double)'
/extruder.h:411: note: candidates are: extruder::extruder()
/extruder.h:411: note: extruder::extruder(const extruder&)
extruder:309: error: no matching function for call to 'PIDcontrol:IDcontrol(byte, byte, int)'
/extruder.h:371: note: candidates are: PIDcontrol:IDcontrol()
/extruder.h:371: note: PIDcontrol:IDcontrol(const PIDcontrol&)
extruder:314: error: prototype for 'PIDcontrol:IDcontrol(byte, byte, bool)' does not match any in class 'PIDcontrol'
extruder.h:371: error: candidates are: PIDcontrol:IDcontrol(const PIDcontrol&)
extruder.h:371: error: PIDcontrol:IDcontrol()
extruder.ino: In member function 'void PIDcontrol::internalTemperature(short int (*)[2])':
extruder:344: error: 'temp_pin' was not declared in this scope
extruder.ino: In member function 'void PIDcontrol::pidCalculation(int)':
extruder:439: error: 'heat_pin' was not declared in this scope
extruder.ino: At global scope:
extruder:614: error: prototype for 'extruder::extruder(byte, byte, byte, byte, byte, float)' does not match any in class 'extruder'
extruder.h:411: error: candidates are: extruder::extruder(const extruder&)
extruder.h:411: error: extruder::extruder()
extruder.ino: In member function 'void extruder::setDirection(bool)':
extruder:749: error: 'motor_dir_pin' was not declared in this scope
extruder.ino: At global scope:
extruder:752: error: prototype for 'void extruder::setCooler(byte)' does not match any in class 'extruder'
extruder.h:418: error: candidate is: void extruder::setCooler(int)
extruder.ino: In member function 'void extruder::sStep()':
extruder:782: error: 'motor_step_pin' was not declared in this scope
extruder.ino: In member function 'void extruder::enableStep()':
extruder:789: error: 'motor_en_pin' was not declared in this scope
extruder.ino: In member function 'void extruder::disableStep()':
extruder:794: error: 'motor_en_pin' was not declared in this scope