*SOLVED* Executing SimpleTimer from within a library

Good to hear it is solved,

To keep the library backwards compatible you could use this construct

#if defined(ARDUINO) && ARDUINO >= 100
  #include "Arduino.h"
#else
  #include "WProgram.h"
#endif

This way the compiler can select the right #include based upon the Arduino version.

Similar code constructs exists based upon board type.