I'm not sure if this might be it, but I'm just throwing it out there.

Possibly because of lack of activity, Google may have turned on security measures to prevent hackers or someone else from accessing your account. I'm not sure if a Gmail account is attached to your profile or not, but if you have one, you should have a message that allows you to change security options so you can upload videos. If not, you'll have to come up with a Gmail account with that email.

I hope this helps.