But now appears other error. #$ /usr/local/pgadmin3/bin/pgadmin3 /usr/local/pgadmin3/bin/pgadmin3: error while loading shared libraries: /usr/lib64/libpq.so.5: ELF file OS ABI invalid
ldd doesn't find it too. Kind of strange. How did you install libpq? did you install the 32-bits library? (which would explain where it is located and why ldd didn't find it). But it won't explain why you could compile without the library.