3)	[done]
The check on the value for the Other amount would probably be better if it was done on the onchange event rather than a submit. You also currently have the message displaying in 2 spots, we only need it to display below the Step 2. Choose Sponsorship Category text. Take out the one at the top of the page.
The check you also do to see if it’s a valid number displays the error in 2 spots, same comment as above, only have it directly above the field. Also, this would be better checked in an onchange event rather than the submit. To ensure they get the message, maybe put a button beside the entry field with a label of “Enter”. The button does not have to do anything, having it there will ensure they are leaving focus of the text field and the check on the entry runs prior to them hitting the submit button.