We are experiencing an odd problem with Saxon inside of a WebLogic version 9.2 Container.  When the application starts up it is able to load the XSL file fine and the transformer object is able to transfor the XML just fine.  Eventually, usually after 2 or 3 days of continuous uptime with not too heavy usage Saxon starts to throw this exception when loading a style sheet which has previously worked.  Once it starts having this issue all stylesheets fail to load with the same message. 
 
Here is the exception:
com.qwest.ecomm.xslt.XTPoolableObjectFactory INFO  2009-02-24 09:17:36,961 - Creating new XT object, XSL=./xsl/nw/ViewEBill.xsl
com.ecomm.xslt.XSLTObject INFO  2009-02-24 09:17:36,961 - TransformerFactory hard class=class weblogic.xml.jaxp.RegistrySAXTransformerFactory
com.ecomm.xslt.ECSSURIResolver INFO  2009-02-24 09:17:36,965 - href=lib_Common.xsl
com.ecomm.xslt.ECSSURIResolver INFO  2009-02-24 09:17:36,965 - base=file:///prod/ecom2/local/apps/apps92/5.0.0.22/xsl/nw/ViewEBill.xsl
com.ecomm.xslt.ECSSURIResolver INFO  2009-02-24 09:17:36,966 - Location of included file took 1ms to find.
com.ecomm.xslt.ECSSURIResolver INFO  2009-02-24 09:17:36,969 - href=lib_CreateEncryptedUrl.xsl
com.ecomm.xslt.ECSSURIResolver INFO  2009-02-24 09:17:36,969 - base=file:/prod/ecom2/local/apps/apps92/5.0.0.22/xsl/nw/lib_Common.xsl
com.ecomm.xslt.ECSSURIResolver INFO  2009-02-24 09:17:36,971 - Location of included file took 2ms to find.
com.ecomm.xslt.ECSSURIResolver INFO  2009-02-24 09:17:36,972 - href=lib_FormatColumnTitles.xsl
com.ecomm.xslt.ECSSURIResolver INFO  2009-02-24 09:17:36,972 - base=file:/prod/ecom2/local/apps/apps92/5.0.0.22/xsl/nw/lib_Common.xsl
com.ecomm.xslt.ECSSURIResolver INFO  2009-02-24 09:17:36,974 - Location of included file took 2ms to find.
com.ecomm.xslt.XSLTObject ERROR 2009-02-24 09:17:36,983 - Caught generic exception while creating a transformer object.
java.lang.ArrayIndexOutOfBoundsException: 5
 at net.sf.saxon.om.NamespaceIterator.getInScopeNamespaceCodes(NamespaceIterator.java:170)
 at net.sf.saxon.tree.ElementWithAttributes.getInScopeNamespaceCodes(ElementWithAttributes.java:260)
 at net.sf.saxon.style.LiteralResultElement.validate(LiteralResultElement.java:198)
 at net.sf.saxon.style.StyleElement.validateSubtree(StyleElement.java:1167)
 at net.sf.saxon.style.StyleElement.validateChildren(StyleElement.java:1201)
 at net.sf.saxon.style.StyleElement.validateSubtree(StyleElement.java:1176)
 at net.sf.saxon.style.StyleElement.validateChildren(StyleElement.java:1201)
 at net.sf.saxon.style.StyleElement.validateSubtree(StyleElement.java:1176)
 at net.sf.saxon.style.XSLStylesheet.preprocess(XSLStylesheet.java:643)
 at net.sf.saxon.PreparedStylesheet.setStylesheetDocument(PreparedStylesheet.java:279)
 at net.sf.saxon.PreparedStylesheet.prepare(PreparedStylesheet.java:117)
 at net.sf.saxon.TransformerFactoryImpl.newTemplates(TransformerFactoryImpl.java:130)
 at net.sf.saxon.TransformerFactoryImpl.newTransformer(TransformerFactoryImpl.java:85)
 at weblogic.xml.jaxp.RegistryTransformerFactory.newTransformer(RegistryTransformerFactory.java:209)
 at com.ecomm.xslt.XSLTObject.<init>(Unknown Source)
 at com.ecomm.xslt.XTPoolableObjectFactory.makeObject(Unknown Source)
 at org.apache.commons.pool.impl.GenericKeyedObjectPool.borrowObject(GenericKeyedObjectPool.java:747)
 at com.ecomm.services.ECSS.doTransformation(Unknown Source)
 at com.ecomm.services.ECSS.fetchScreenContent(Unknown Source)
 at com.ecomm.services.ECSSProxy.fetchScreenContent(Unknown Source)
 at sun.reflect.GeneratedMethodAccessor60.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:585)
 at weblogic.webservice.component.javaclass.JavaClassInvocationHandler.invoke(JavaClassInvocationHandler.java:134)
 at weblogic.webservice.core.handler.InvokeHandler.handleRequest(InvokeHandler.java:105)
 at weblogic.webservice.core.HandlerChainImpl.handleRequest(HandlerChainImpl.java:144)
 at weblogic.webservice.core.DefaultOperation.process(DefaultOperation.java:551)
 at weblogic.webservice.server.Dispatcher.process(Dispatcher.java:204)
 at weblogic.webservice.server.Dispatcher.doDispatch(Dispatcher.java:175)
 at weblogic.webservice.server.Dispatcher.dispatch(Dispatcher.java:97)
 at weblogic.webservice.server.WebServiceManager.dispatch(WebServiceManager.java:101)
 at weblogic.webservice.server.servlet.WebServiceServlet.serverSideInvoke(WebServiceServlet.java:321)
Any ideas as to what the problem could be?
                                                    
Paul Ackley
Staff Software Engineer
Qwest Communications