Question: Why do I get the warning solutions may have been lost when solving RootOf?

Hey guys, 

From a former calculation I got a set of points as a implicit RootOf function for an intervall. Now I want to check, if these points are in a certain area. So i thougt I take the RootOf function, the intervall and the inequalities (which describe the target area) and use the solve command. But then I get the warning, solutions may have been lost and no solution. When you draw the implicit function you can see thats in the right area (above y=1 and below y=x). So there should be a clear anwer, giving me back the whole RootOf function in the intervall.

Download QUESTI~2.MW

Since there was an error uploading the picture here the code 

restart;
Sol := {x = RootOf(_Z^2 - y, index = real[2]) + 1, 1 < y, y < 2};
area := {1 < y, y < x};
Sol_area := solve(Sol union area);
print(Sol_area);

So why do I get this warning, the calculation seems quite easy? And is there a workaround? Or a diffrent kind of solve function? SemiAlgebraic is as far as i know only for polynomials. So I got an error as well. Since the websites are down I could start an own reasearch before. So thank you in advance. 

Regards

Felix