I just upgraded to paid account but I can't upload files to my ftp account.
On two different clients the message that show: "not logged on, free users or subusers can have 2 connections only. Please upgrade to premium service on www.drivehq.com. Price starts at $2.99/month".
What could be the problem?

If you just ordered a new subscription and if you were actively using the FTP service, the account status probably is not updated immediately.  Please stop using the service for 10 minutes, then try again. Also, please logon www.drivehq.com and go to My Account page to check the order status, make sure your account is a Paid Account.

It's working now. I just did what you said.
Thanks.