If you tell me what the error message is, then I might be able to explain to you what it means.
Think about the person responding to your questions. Try and make their life a bit easier. The chances are that anyone who can answer your question will be familiar with the error messages, and will be able to respond much more quickly if you supply the message.
Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference