What are you trying to enter?  The drop down box under the "plan" heading is the key for the form.  Unless they were in a plan that they were exempt from paying Social Security, the form really isn't applicable.

Yes, thanks, the answer helped me to enter the necessary input.. Also, while doing more research I found an interesting qualifier for deducting pension payments from states other than Minnesota.  The "other state" must allow Minnesotans the same type of deduction on their tax return.