The name of a user parameter can be arbitrary, but subject to certain rules.
Names in command language should start with an alphabetic character followed by alphanumeric characters.
They are allowed to contain embedded spaces.
Underscores are reserved for future syntax and, as such, are not allowed.
The name "Workbench Path Parameters" is a reserved name. For details, see User Fortran in Ansys Workbench.
However, to enable access to the parameter on the solver side by using the same name, you should ensure that the names of user parameters contain only single spaces and are unique in the first 20 characters.