I found this online, see if it helps:
-Launch Cydia and uninstall Display Recorder. To do this, simply tap Manage, tap Packages, scroll down to Display Recorder, tap it, tap Modify in the upper right corner, and select Remove. Confirm the uninstallation in the dialog that appears, and tap Restart Springboard when prompted.
-Launch iFile and navigate to /var/mobile/Library/Keyboard/
-You will see some booleanmagic license files, a folder titled DisplayRecorder, and some other system files.
-Tap the Edit button in iFile, select the booleanmagic files and the DisplayRecorder folder (your selection will be marked by the filled bubbles to the left of each file) and tap the Trash Can icon at the bottom of iFile’s interface. Do not delete any other files, as you may create problems with your iOS keyboard. Confirm the delete, and respring (via SBSettings or similar. Otherwise, just turn your device off and then on).
-Go back to Cydia and install Display Recorder again. When you try to record this time, you should not encounter any errors.