Did you try viewing the camera from a different PC? Are the results are the same?
If the above recommendation does not work, then try performing a factory reset on the DCS-2230. While the DCS-2230 is powered-on, using a paperclip, press and hold the recessed button on the rear of the device for > 6 seconds. This procedure will delete any user defined settings you entered into the camera.
If none of the above solves this issue, you may have a bad camera and should contact D-Link for an RMA.