When you say "upload a video", do you mean when you import a video into your Premiere Elements project?
What model of camcorder is this video coming from and what format and resolution is it? Did you use Premiere Elements to get the video from the camcorder to your computer?
Also, where did you get your installation file for Premiere Elementns: A download from Adobe? The boxed set?
Downloads from the App Store have been notoriously buggy.
correct, when I import into the new project. I downloaded the content off my GoPro 3+ black edition which was recorded in 1080p at 30FPS and onto my Mac. I bought the box CD set and this is my first project im attempting to create.
Although Premiere Elements 12 usually sets up projects automatically to match a video's specs, you may need to do it manually for this type of video.
Start a new project. On the New Project screen, click Settings. Select the AVCHD 1080p60 preset.
Then try to add the video to this project. (Try starting with a short clip, just to see if it works.)
BTW, you do have at least 4-8 gigs of RAM on your MacBook, right?
GoPro video should work as is... if it doesn't, read below about converting with GoPro software to an easier to edit codec
-use to convert http://gopro.com/software-app/cineform-studio/