xml publisher namespace prefix 'ref' used but not declared

Actual Error when you open OPP LOG File using Link(http://rajesh-for-u.blogspot.in/2013/12/one-or-more-post-processing-actions.html)
We can see below error when you search with request id.

java.lang.reflect.InvocationTargetException
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:597)
     at oracle.apps.xdo.common.xml.XSLT10gR1.invokeNewXSLStylesheet(XSLT10gR1.java:558)
     at oracle.apps.xdo.common.xml.XSLT10gR1.transform(XSLT10gR1.java:228)
     at oracle.apps.xdo.common.xml.XSLTWrapper.transform(XSLTWrapper.java:177)
     at oracle.apps.xdo.template.fo.util.FOUtility.generateFO(FOUtility.java:1044)
     at oracle.apps.xdo.template.fo.util.FOUtility.generateFO(FOUtility.java:997)
     at oracle.apps.xdo.template.fo.util.FOUtility.generateFO(FOUtility.java:212)
     at oracle.apps.xdo.template.FOProcessor.createFO(FOProcessor.java:1657)
     at oracle.apps.xdo.template.FOProcessor.generate(FOProcessor.java:967)
     at oracle.apps.xdo.oa.schema.server.TemplateHelper.runProcessTemplate(TemplateHelper.java:5888)
     at oracle.apps.xdo.oa.schema.server.TemplateHelper.processTemplate(TemplateHelper.java:3438)
     at oracle.apps.xdo.oa.schema.server.TemplateHelper.processTemplate(TemplateHelper.java:3527)
     at oracle.apps.xdo.oa.cp.JCP4XMLPublisher.runProgram(JCP4XMLPublisher.java:683)
     at oracle.apps.fnd.cp.request.Run.main(Run.java:161)
Caused by: oracle.xdo.parser.v2.XPathException: Namespace prefix 'ref' used but not declared.
     at oracle.xdo.parser.v2.XSLProcessor.reportException(XSLProcessor.java:782)
     at oracle.xdo.parser.v2.XSLProcessor.newXSLStylesheet(XSLProcessor.java:564)
     ... 17 more




I have seen this intermittently... sometimes when you doubleclick on a form field it will open a 'BI Publisher' field properties text box which allows you to insert/change xml syntax for field. But, doing so will put a <?ref: 0000xx?> in the actual form field help text box.
This will work on BI publisher desktop but will give you the ref namespace error on server.
You will have to check each form field in your template to make sure that there is no ref: element in any of the form fields.

while desiging the template using 11.1.1.3 or 11.1.1.5 desktop plugin make sure your start designing the template by saving it with backward compatability.

I have faced this problm.what i have done is uninstalled the BI publisher 11.1.1.5 and put the correct tags and run.Thats it...   :)