Do you have to make that selection for you to continue in the upload? Have you remember to complete all the fields besides the one asking about Public, Unlisted, and Private?
Is this a "it worked before but not now" or "it never worked before" type matter.
What are the properties of your source media, what have you selected as the project preset, and what specific YouTube export setting are you designating for your upload? What is the file size and duration according to the YouTube export dialog?
Can you export that Timeline to a file saved to the computer hard drive and then upload the file from the hard drive save location to YouTube at the YouTube web site?
We will be watching for your follow up to decide what next.
Are you having any other problems with Premiere Elements 8.0/8.0.1?