This is what the documentation says:
e10792-section:5.3.4.2.1 wrote:The following are not acceptable: spaces, tabs, line feeds, carriage returns and ; ^ ? : @ & + " # % < * ~ |
or in some other sections, it is mentioned : spaces are not allowed. That may be or may not be the reason for the error resulting from what you did. (I'm just inspired by the error message, otherwise I am not sure.)