UTR Library Designer Error

Template 5'-UTR Sequence (25NT) : AGTTAGGTCCAAAGGAGCATCACTT ,     Additional Constraints for designing 5'-UTR sequence (25NT) : AGTTAGGTCCAAAGGAGNNNNNNN ( Length should be 25NT )

Protein Coding Sequence (at least N-term 35NT) : ATGTCGACTCACACATCTTCAACGCTTCCAGCATT

16s rRNA Sequence : ACCUCCUUA

Desired Expression Range : 200.00 ~ 500000.00

Number of expression-level intermediates : 8