Well let see, some things that MIGHT have been helpful right off the bat:
It may have been worth the effort to tell us that you were working with the opal library and were trying to extend the hgeEntityEx -- I have never used the opal library myself, but maybe someone had an example they could have shared.
I personally though that hgeEntityEx was some class you made.
It would be nice to see the class definition (at least the broad stokes) for entSamusAran.
It would have been nice to see the actual line the error occured on (though I think bench correctly diagnosed the "no appropriate default constructor available" problem).
AS for the linker error... what headers are you using in your file? It looks like you are including something twice.