BB Curve :: ID Not Recognised By Phone?

I set up my Blackberry, and it's been working fine for a month or two. However, my work email periodically forces me to change the password for security reasons. Unfortunately, having done this I tried to do so on my Blackberry Curve, and it asks for my Blackberry ID.I have a Blackberry ID. It works fine. I can log into my account on a PC, and use it to access Appworld. However, when I tried to do it on the phone, it didn't work. I checked the email, double checked the email, checked the password, double checked the password. All fine. Out of frustration, I went to "forget password" on the phone, thinking maybe if I reset it that would work.

I got this message:"Your request cannot be completed. Please ensure that your Blackberry ID has been activated and that you have typed the correct email address"I am tearing my hair out here. I know my Blackberry ID. I am looking at it on my PC where I have logged in, yet my phone now thinks it doesn't exist?