Thanks for the reply.
I found this all to be pretty weird. I use a program on my computer called dbPowerAmp to convert my CD's over to MP3's and in their last release that I recently installed their new default format is not MP3's it's a format called FLAC. Well, Lexus apparently does not like the FLAC format so I had to use one of their other programs to convert my recent CD burns from FLAC to MP3. I then did a bulk copy of the music folders from my PC to my memory stick and I kept trying to read the stick on accessory instead of with the motor running. I could plug my MP3 player from SONY into the USB while in accessory mode and the card would play music from the player but if I disconnected the player and plugged in the memory stick in instead, the car would not read the memory stick. However if you turned the car on with the memory stick plugged in as soon as the car started the LED on the memory stick lit up and I was able to play music. But then I discovered that when I selected an album the order in which the car started playing the songs was not the order they were played on the corresponding CD. Also the order in which albums show up when you select FOLDER UP in no way corresponds to any order I can figure out. I do believe that I've determined that to get the car to play the songs from the memory stick in the same order as the songs on the CD you need to create a folder on the memory stick and then copy the songs from my PC into that new folder on the memory stick one song at a time in the same order as they were on the CD. This is all pretty crazy but it now seems to be working.