It is not a software error, kinnem is correct about them being in the same unit.
There is a pdf document that the website advised you to read before starting the scholarship application. Not trying to be mean but if you had read it thoroughly, as the website instructed you to, it would have told you the exact answer to your question.
It says that you must list 5 different units for your choices. GU, GWU, and UMCP are the same unit, so for this purpose you would select only GWU and that would be only one choice, meaning you would need 4 more different units.
You can still apply to (and use the scholarship at) GU and UMCP, but the navy wants 5 different units for the NROTC Application