Cocoon 1.8.2

Error found handling the request.

org.apache.cocoon.processor.ProcessorException: Could not associate stylesheet to document:  no matching stylesheet for: unknown
	at org.apache.cocoon.processor.xslt.XSLTProcessor.getResource(XSLTProcessor.java:236)
	at org.apache.cocoon.processor.xslt.XSLTProcessor.process(XSLTProcessor.java:113)
	at org.apache.cocoon.Engine.handle(Engine.java:384)
	at org.apache.cocoon.Cocoon.service(Cocoon.java:183)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:588)
	at org.apache.jserv.JServConnection.processRequest(JServConnection.java:317)
	at org.apache.jserv.JServConnection.run(JServConnection.java:188)
	at java.lang.Thread.run(Thread.java:484)