What computer operating system is your Premiere Elements 12 running on? Have you updated from 12 to 12.1 in an opened project's Help Menu/Update?
Now for the immediate issue...Premiere Elements 12 content should be for all intents and purposes the same as Premiere Elements 11.
Please check out my Premiere Elements 12 First Look blog (especially part 3 content) where I did a microscopic look at the differences between 11 and 12.
and any surprises should be included in
Did you stay with Windows as you went from Premiere Elements 11 to 12?
Let us go through a check list see if we can figure out what is going on in your computer environment...for now I will assume Windows 7, 8, or 8.1 64 bit.
1. Are you running the program from a User Account with Administrative Privileges? In addition, have you applied Run As Administration to the program by right clicking Premiere Elements 12 desktop icon and selecting Run As Administrator.
2. How long have you waited for the contents under the Audio Tab to appear. Many have observed that there is a delay between what appears to be installation of the program and the appearance of Music Scores and Sound Effects. Leave the program open and give it time.
3. I almost overlooked a thought since you said that you worked with 11 already. But, I had better ask to make sure I am not taking anything for granted.
In Premiere Elements 12, are you looking in the Expert workspace or the Quick workspace? If you are working in the Quick workspace, that could be contributing to your issue.
Please review and then we can decide what next. You are not looking at a Premiere Elements 11 versus 12 issue, rather a problem in your specific computer environment.
Thanks for the follow up with the wonderful news "It is now working." Lots of details to sort through, so you did a great job in sorting through the troubleshooting.
Please never hesitate to ask questions and to ask for clarification. We are glad for the opportunity to be of assistance.
Best wishes as you move forward in your Premiere Elements workflows.