This message is displayed if you are trying to assign a non-valid name to a project node.
For VBScript, the name is valid if it begins with a letter and does not contain spaces. For JScript, JavaScript, Python, DelphiScript, C++Script and C#Script, the name is valid if it begins with a letter or an underscore and does not contain spaces.
Letters, digits, and underscores are allowed after the first character.
This rule doesn’t apply to project items which cannot be called from script code by their names. An example of such items is feature files below the Scenarios project item.