What computer operating system is your Premiere Elements 12 running on? For now I will assume Windows 7, 8, or 8.1 64 bit.
Have you updated 12 to 12.1 Update using an opened project's Help Menu/Update? If not, please do so.
We would need to know more about your project settings and the properties of your source media, but here is the generalized
idea...assuming a 1920 x 1080 @ 29.97 progressive frames per second project....
1. Try to export your Timeline content to an AVCHD.mp4 file (1920 x 1080 @ 29.97 progressive frames per second or 1280 x 720 @ 29.97 progressive frames per second)
with Presets = MP4 H.264 1920 x 1080p30 or with Presets = YouTube Widescreen HD
From the computer hard drive save location for this AVCHD.mp4 file, upload the file to YouTube at the YouTube web site.
Is the upload successful?
What is the estimated file size as well as the known duration of the Timeline content that you want to upload to YouTube from
within the Premiere Elements feature?
Please review and consider and then we will determine our next troubleshooting steps.
Computer operating systems is Microsoft Windows XP with X86 based PC (32 bit). I have upgraded to 12.1. Going to try uploading a project / file using the YouTube Widescreen HD presets and see if that works (may be a few days before I can get back to you though on if it was successful or not). File size is anywhere from 2.0 GB to 3.0 GB and duration ranges from 40 minutes to 1 1/2 hour depending on particular file. Thanks for the help.
Thanks for the follow up.
Just in case note...the Premiere Elements 12/12.1 Publish+Share/Social Websites/YouTube will not process a file size over 2.0 GB/15 minutes even if you have a YouTube account with extended space and duration. So, if your Timeline is exceeding the Premiere Elements 12/12.1 limits for its YouTube feature, then
you are forced to export your Timeline to a file saved to the computer hard drive and from there upload the file to YouTube at the YouTube where your extended space and duration account can be used. That account will not work in the Premiere Elements feature. If you have a regular YouTube account, then you will have to apply for an extended space and duration account at YouTube in order for YouTube to process your file size exceeding 2.0 GB and duration15 minutes.
We will be watching for your progress when your schedule permits.