Diagnosis
As a result of your entry, the residual budget on fundscenter/commitment item &V1&, which was reserved for the budgetcarryforward, has now become negative.

Procedure
If you have not reserved any residual budget for the budgetcarryforward, you have to enter a positive amount.
If you want to reduce reservations that have been entered so far, youhave to change the entered amount in a way that the total of allreservations entered is positive.