Help submitting IMM5708E document

[BlueOwl]

Hi,

I am in Canada on an IEC visa and am looking to extend my stay as a Visitor. I have all the documentation ready to go but have so many problems dealing with the CIC website to submit my documentation.

I have filled out the pdf electornically, clicked the box for "New temporary resident visa
(For valid Study or Work Permit holders ONLY)" and have Validated the document. I go to upload the file and get this message:
To apply for a temporary resident permit, please complete the application on paper and submit it to a CIC office. When applying online, please ensure that the checkbox titled "initial temporary resident permit or extension of temporary resident permit" is not checked on the application form.

When I untick the box and save the pdf, I then get this: We are unable to validate your document at this time, please retry later.

I have tried this numerous times now and it has taken a week off my times and I'm getting fairly stressed about it. I have tried submitting the files in both IE and Firefox, any ideas, anyone?