I have a CLLE program in which I pass two parameters, the first is a one character field, the second is a 600 character field. When run, the parameters come in correctly. But when I substring the second parameter into 40 fifteen character pieces it gives me a CPF0804 error half way through the string. I got around this problem by defining another field as 1200 characters and setting the value the same as the 600 character field. Then I use half of the 2400 character field in the substring to get my 40 values. Why does this not work correctly - or is my solution the only way out?