Entertainment Networks cannot be built

I have been playing Galactic Civilisations 3 for years in its many forms, and GC2 before that. I have had no serious problems to date. On Sunday I decided to purchase (through Steam) the Worlds in Crisis DLC to complete the game, and also downloaded the V4.01 update. Before Sunday I was able to build Entertainment Networks when I completed the Xeno Entertainment tech; after the Sunday update I found that Entertainment Networks do not appear in the build list. Gem Trader and Entertainment Capital appear on the list, and Celebrity appears on the Citizen screen, but no sign of ENs. I have tried several different races, none of them can build ENs; I have tried the game on Easy and on Normal; I have verified the integrity of game files on Steam; I have uninstalled the game and reinstalled it; but nothing I try makes the ENs available on the planet building screen.

Please help! I really enjoy GC3 and I just want to be able to play it again. I have saved files which I can email to you to illustrate the problem.