This message is displayed when you give an invalid name to a project item or its child element. The name is used to refer to the item from scripts, so it must be a valid script identifier. Supported scripting languages use different rules for identifiers, however, you can easily make a name adoptable for any scripting language: start a name with a letter (in JavaScript, JScript, Python, DelphiScript, C++Script and C#Script names can also begin with an underscore), and use only letters (A..Z, a..z), digits (0..9) and underscores (_) in it. Spaces and other characters are not allowed in names.