I've been trying to use the substring function to create a variable but it keeps failing. [8099 - Set Variable] An unexpected error occurred. Function 'Substring': Parameter '1' must be a string value. Function definition: 'Substring(text, startPos[, length]) returns string' Original expression: Substring(CurrentFile, 27,20).

${Substring(CurrentFile, 27,20)}

CurrentFile is a FileList variable.

Then apply the "String" function:

${Substring( string(CurrentFile), 27,20)}