It sounds as your communication settings aren't correct. Do the following test to verify that you are using the correct communication settings.

1. Unplug the cutter,
2. Open SignCut,
3. Click the Cutter button
4. Pull down the Output Device / Port list
5. Make a note of what your choices are.
6. Plug the cutter back in, and turn the power on.
7. Look at the same device output list again, and now you should see a new port. This is the port for your cutter, choose it.
8. Now please walk over to your cutting plotter and look in for a setting in the display called Baud or BR and lock for the value it is set to.
9. Go back to your computer and enter the same value in SignCut in the cutter dialogue.

Your communication settings should now be correct. Go to the Cut Out icon represented by a pair of scissor and do a test cut. Notice certain cutters require you to download a driver to be able to find the communication port in SignCut. Please contact the manufacturer of your plotter to help you get the drivers you need.