XML Schema Issue

I would still like the option to export the Schema Library to an XML file so I've been working on writing an XML Schema file to validate against.

I'm familiar with XML, but I've never worked with XML Schema before. I understand it for the most part, but I've run into an error when it comes to validating. The validator output is not very helpful! All I can tell for now is that:

Element 'element' is invalid, misplaced, or occurs too often.

I'm not sure that the XML Schema is required to parse an XML document successfully, but I'd prefer to have it just in case. Of course, this is a relatively minor feature so I don't want to spend a huge amount of time on it at the moment.