Simulink code generation error during make process when a subsystem is copied from one model to another. object files not generated for stateflow blocks that are copied.

When I copy to/from a model to another model, I receive code generation error and the code generation aborts during make. I noticed that the object files are not generated for any stateflow blocks that are copied to/from the model. I am using R2014a. Any suggestions please? gcc.exe: c5_Corona.obj: No such file or directory gcc.exe: c22_Corona.obj: No such file or directory gcc.exe: c30_Corona.obj: No such file or directory gcc.exe: c35_Corona.obj: No such file or directory gcc.exe: c40_Corona.obj: No such file or directory gcc.exe: c43_Corona.obj: No such file or directory gcc.exe: c51_Corona.obj: No such file or directory gcc.exe: c63_Corona.obj: No such file or directory gcc.exe: c71_Corona.obj: No such file or directory gcc.exe: Corona_sfun_registry.obj: No such file or directory gmake: * [Corona_sfun.mexw64] Error 1

Thanks