Hello guys!
When applying for my study permit, I found that instead of printing the 'study application' document to a .pdf file, saving the file on my computer worked! Please keep in mind that you must have a 'successful validation' in order for this to work. Once you've gotten a successful validation notification, check for a 'file' option in the upper left hand corner of your screen, then click on where it says 'save as.' Save the file to a convenient location (which can be your desktop or a commonly used folder.) Return to your application on the official Canadian website and retry uploading your file/document. This method worked for me! Best of luck!
File ---> save as