How many instances of this "video ..moving up and down" do you see through the viewing of the video?
This is basic information that is needed to answer this type of question (See John T. Smith comment.)
However, these are the basic questions that I would need answers for in order to gauge the issue and make suggestions.
1. What version of Premiere Elements are you using and on what computer operating system is it running?
2. What are the properties of the source media that you are putting on that Timeline? And, do the properties of these source media match the project preset that you or the program is selecting for the project preset? Among the video properties of interest...does the video have an interlaced or progressive frame rate and what is the frame rate? Are you applying a lot of effects to the footage? Have you applied Field Options, Anti-Flicker, special transitions, motion effects, etc?
3. Are you uploading your Timeline to YouTube from within Premiere Elements? Or are you exporting a Premiere Elements export file to the hard drive and then uploading the file to YouTube at the YouTube web site? Whatever the case, details please.
Thanks for getting back to this, I will get the answers to the questions when I get home and let u know. I really appreciate your time and help.