For operands of a binary operation, the data type DT_STR is supported only for input columns and cast operations. The expression ...

For operands of a binary operation, the data type DT_STR is supported only for input columns and cast operations. The expression "%1!s!" has a DT_STR operand that is not an input column or the result of a cast, and cannot be used in a binary operation. To perform this operation, the operand needs to be explicitly cast with a cast operator.