The processor power may be to low. Try to slow writing and drawing.
Where are greetings stored?
For each greeting a video file and an image file with the most recent snapshot is stored, the video file in the directory /movies/PersonalGreetings on the SD card or in internal storage. The name of the video file is: YYYY-MM-DD_hh-mm-ss.3pg
with year, month, day, hour, minute, second when greeting was stored in the archive. The corresponding name of the image file is: YYYY-MM-DD_hh-mm-ss.jpg which is stored in the directory /pictures/PersonalGreetings.