It looks like in your case, you dragged a Hot Water Coil onto the Plant Loop, but this coil is not inside of a PTAC or attached to an Air Loop. I would try deleting the coil then following these steps to add a PTAC:

1. On the Thermal Zones Tab, drag a PTAC from the library into each zone

2. Click on each PTAC

   1. Click on the Chain Link icon in the upper right
   2. Click the check box to connect the PTAC to the Hot Water Loop (which you've already created)