Is this a Warning? If so, you can go ahead and e-file. I just tried one with just the number input for carryover and no child. I got a warning that all the information should be entered.

Lacerte has https://accountants.intuit.com/community/tkb/choosetemplatepage/board-id/diagnostics/search-before-p... to look up the diagnostic numbers (not very complete, but ...) You could enter the number you see in ProConnect and see if it shows up. 

You can try to e-file and see what happens, you should know right away if it can be filed.