Although we do not support third party hardware such as your DVR DHI-XVR4232AN-S2, I would recommend double checking all of your record schedule settings and also the state of your HDD. Another thing to look for is make sure the recorder is set to overwrite the oldest files as the HDD becomes full. Some recorders may be set for "stop record" when the HDD gets full.
I would recommend contacting your supplier for further assistance. Hope this helps!