No, not a problem of FSUIPC.
FSrealWX lite is no longer being developed.
Probably the airports are not stored in FSrealWX lite.
Use FSrealWX v2 to get further support.
If you find an error, then please give me exactly about your system. Which sim (FSX / P3D / Xplane). Which connection (FSUIPC / SimConnect / FSrealWX-Bridge). Which OS.