I wanted to thank you publicly for all the help and advive you gave me outside this forum. I appreciate your sticking with it until the problems I encountered in upgrading were finally solved. Thanks.
In case others experience similar problems, the main difficulty was that the "uploaddata" directory and a "sessions" subdirectory did not install. Transferring the "uploaddata" files from the old directory and creating a new, empty "sessions" directory eliminated the error message. At this point I was still unable to login. After different attempts, finally, choosing a chmod permission of 777 for these these two directories got things going as they should be.