It wants me to link my W-2 to a schedule C, but I don't have a schedule C filed, nor do I want to file one. I can't file my federal taxes without resolving this.

Return to the area where you entered your W-2.  Click the "edit" button next to your W-2 that has the statutory employee box checked to review your entries.  Say no to the screen that asks if you have any expenses related to the statutory employee W-2. Note: if you are not a statutory employee then uncheck the box.  (see attached screenshot)