Here's the solution they gave me, and so far it works.

On the Admin workstation, go to C:\ProSeries\ProNet17\Updates. Delete all the files below the .htm files. Then go to C:\ProWin17 and open inventory.dat in notepad. Delete all the lines above "Components" and save the file. Then run ProSeries update and it should work without crashing.

I have yet to test the other workstations to see if it works there.

Note: these are the instructions for a network install. Procedure will likely be different for a standalone install.