C:\Program Files\Arduino\libraries\MG\MGLED73.cpp: In constructor 'MGLED73::MGLED73(int, int, int, bool)':
C:\Program Files\Arduino\libraries\MG\MGLED73.cpp:7: error: no matching function for call to 'MGLED7::MGLED7()'
Start fixing the errors from the top down. This one should be dirt simple to fix. You are trying to call a no argument constructor for the MGLED7 class in the MGLED73 class. There are no versions of the constructor that take no arguments. So, quit trying to call the no argument version, or create a no argument version that can be called.