I searched the DigiWeigh website and got the instructions for calibrating the scale, which may be your problem. I don't know if you have the manual, which is available only as a Word document. http://www.digiweighusa.com/bzmanual.doc

HOW TO CALIBRATE THE SCALE

Although your scale was calibrated before shipping, due to different gravity in different part of the globe, a from-time-to-time calibration will keep your scale always accurate.

In the status of OFF, hold both TARE key and MODE key and press ON/OFF button and release all buttons when the screen shows ??CAL?. Hereinafter the screen will show a negative figure, which is its internal code. Wait until the internal code stays on a certain figure, press the MODE button and the screen shows ??ZERO? and then internal code. Put standard weight on the platform. (Please refer to the following standard weight for your model)

Model DW-250BZ

250 gram Class 4 and up

Model DW-350BZ

350 gram Class 4 and up

Model DW-500BZ

500 gram Class 4 and up

Wait until the internal code stays on a certain figure, press the MODE button, the screen shows weight of the standard weight then shows ??PASS? and then weight of the standard weight again. Press ON/OFF button to switch off the scale. Calibration is completed.
If you still have a problem try e-mailing them.
Oh, and if you do e-mail them refrain from using terms like 'eighth' or 'weed' or anything else pertaining to drugs.