When I click on the bulk upgrades button, I'm told I don't have permission

When I click on the bulk upgrades button on my site, it takes me to a page with the message:

You do not have sufficient permissions to access this page.

It also doesn't go anywhere when I click on the Paypal button to upgrade a single site. I click the option I want, then the Paypal button, but it just loads in the same page.