have a Pearl. I am very happy with my phone, but I had many problems with the trackball. I bought a second Pearl, and I encountered identical problems. Sometime I can't move left, right, up or down. Sometime I can’t push (when I push, nothing happens). Sometime it is even worst. The phone get crazy and works by itself : it initiates calls ,sends sms, or other things.I believe this happens because of the trackball.
Today it sent 15 sms to the same person!
A few days ago I wrote a thread on this subject,but it doesn't seem many users complain about this problem.
I believe the trackball on Pearl is the same they have on the 8800 Were they able to improve the trackball quality? It is very strange they have dropped the trackweel that was troubles free, with the trackball if it makes so many problems. I believe I didn't buy the only two units with these problems

A lot of people report having this problem. It is usually dirt or lint or something under the trackball. I haven't had this problem, but people have said if you push the trackball down and move it around sometimes it helps. If you look there is a thread that says trackball cleaning for noobs or something.

I use an IPA (Isopropanol Alcohol) solution and it works like a magic. This alcohol is use specifically for electronic components. I get here at work and Im not sure if you can buy it at any store.