@B_Ren8 and I have confirmed the CaptureIt v1.4 is fully functional on the BlackBerry Bold 9900! The best part of CaptureIt is it’s FREE!!! CaptureIt is a a very popular screen capture application for BlackBerry. You could get it officially from m.thetechmogul.com but the site appears to be suspended now.
Here is the download link for CaptureIt v1.4