I found a solution. This worked for me.
Exit from the error check window. This is important. DO NOT try to edit Form 8949 directly. You can enter the adjustment amount on the Capital Asset Sales Worksheet. Go into Forms View and you will find this worksheet. It is listed as Cap Asset Sales in the left side tree. You will probably see the error show up here too. Put a 0 into column G. It will probably be highlighted, and you can see it is blank. Do this for each error. Close Forms View and run the error check again.
This worked for me. Good luck.
