The problem is having PGM in the MME4 DVE and then trying to put MME4 back onto PGM.
You will need to use another ME or MME in the box.
I don't know how many MEs you have or how many keyers you are using on your PGM row. You could - for example - put MME1 into the DVE box, cut your show on PGM until you need the boxes, cut to MME4 on PGM and then cut your box on MME1 until you are done with cutting in the box and then go back to PGM row to cut.
Or you could simply cut the key 1 box sources (if you don't need keys in the box).
Or you could cut your show on a second ME which is also going in to the DVE box then cut between - for example - MME1 & MME4 on PGM.
Or you could use MME4 as your main Program output, put your PGM ME on MME4 ubtil you want it in the box and then cut BGD, Key1 & 2 to put the boxes on & off.
#Carbonite