You have attempted to use a numeric expression as an argument to the LenLANLEN function. The Len function does not accept a numeric expression, but it does accept either a string or numeric variable or a string expression.
You have used a function call or an expression as an argument to Input , Let , Get , or Put . For example, you've used an argument that appears to be a valid reference to an array variable, but instead is a call to a function of the same name. These statements do not accept function calls as arguments.