REBOL 3 Errors: cannot-use

An attempt was made to perform an operation on a value of an incompatible datatype. For instance, when attempting to add a string to a number.

Message:

["Cannot use" :arg1 "on" :arg2 "value"]

Example:

filter-error try [1 + "1"]
** Script Error: Cannot use add on string! value
** Where: 1 + "1"