Mrs. Flynn,
I tried again to get UC, starting from the beginning (after deleting what I had attempted last night). I first installed the seasonssaved file. Next I downloaded the world itself. Then when trying to install, I got the same message in the launcher stating that my request couldn't be processed. So I deleted the file and again went to the UC download site. But this time, I used the windows Edge browser instead of Chrome (which is what I normally use). Well, I double clicked on the UC world file - this time, the launcher opened, and I did not get the message. But nothing happened. It seemed as if the launcher refused to install the UC world. Quite frustrating! Ah well, I did install Lucky Palms and Riverview. But I was really anticipating playing UC after reading about it. Ah well, as the French say, c'est la vie!
Thanks again for your assistance.