this version airport utility dosen't support this base station

This tells us that you likely have a very old AirPort Base Station and that is no longer supported by current version(s) of AirPort Utility. Or, another way to say the same thing is that Apple will not allow you to install an old version of AirPort Utility that you need on newer Mac operating systems.

Let's confirm by having you tell us what the model number of your AirPort Base Station might be and also what version of the Mac operating system that you are running on your Mac computer.

Look on the side of the AirPort Express to find the model number. It is hard to see, but starts with an "A" followed by four numbers.

Example......A1084 or A1088