Obviously something's wrong in the drive train.
I don't have a DW planer, but my old Delta failed on a couple of occasions when the drive chain jumped the sprocket.
My suggestion is to get the parts diagram out and take the cover off again. Your squeal and lack of turning rollers/cutters would lead me to inspect any shaft that has a pulley or gear attached to it, looking for a woodruff (or similar type) key that has slipped out of place.
If you don't have a parts diagram, you can see one online at ereplacements.com.
I don't have a DW planer, but my old Delta failed on a couple of occasions when the drive chain jumped the sprocket.
My suggestion is to get the parts diagram out and take the cover off again. Your squeal and lack of turning rollers/cutters would lead me to inspect any shaft that has a pulley or gear attached to it, looking for a woodruff (or similar type) key that has slipped out of place.
If you don't have a parts diagram, you can see one online at ereplacements.com.