> The error message I am getting is
> 
> "
> file:///c:/Projects/ccm/Partyin.xml; Line #4; Column #51; 
> XSLT Error (javax.xml.
> transform.TransformerException): The prefix "UML" for element 
> "UML:Class" is not  bound.

....
> 
> I have declared UML namespace in both xml and xslt files, and 
> still getting the same problem. 

The XML parser disagrees: it says you haven't declared the UML namespace,
and in the absence of strong evidence to the contrary, I think it's probably
right and you are probably wrong.

(A plea to everyone once again - if you get an error message, quote it.
Don't paraphrase it. The message doesn't say a "node" is unbound, it says a
namespace prefix is unbound. How can we help to diagnose errors when we only
have a garbled version of the error message?) 

Michael Kay
http://www.saxonica.com/