The XPath expression failed to execute; the reason was: internal xpath error.

This one is a very annoying error.

I was trying to read the value from a DVM and despite all my attempts it was failing with the following error.


<bpelFault><faultType>0</faultType><subLanguageExecutionFault xmlns="http://schemas.oracle.com/bpel/extension"><part name="summary"><summary>XPath expression failed to execute. An error occurs while processing the XPath expression; the expression is dvm:lookupValue('Notification_Config.dvm','key','Users','Value','NA'). The XPath expression failed to execute; the reason was: internal xpath error. Check the detailed root cause described in the exception message text and verify that the XPath query is correct. </summary></part><part name="code"><code>XPathExecutionError</code></part></subLanguageExecutionFault></bpelFault>

the reason for this error is that the dvm look up function is very much case sensitive and i was using Key instead of key.

So my two cents when you face this issue just validate if all the cases are matching in the actual dvm and the lookup function.