Error 22. Bad 'format' argument type - format has to be a number (not array)

Format parameter specified in AddColumn() function call should be a number (not array). Example

AddColumn( C, "Close", IIf( C > 10, 1.2, 1.3 ) ); // wrong, format parameter (3rd) has to be a number

AddColumn( C, "Close", 1.3 ); // correct