An integration that have an XML document as input of a DML map broker fails. The following error appears in Integrator's LOG: "Mapbroker execution failed".

Look for the following message in starter.log:
       java.lang.NoClassDefFoundError: org/apache/xerces/parsers/DOMParser
This class belongs to the apache xerces XML parser library.

The previous message says that the Java DOMParser class was not found in one of the the Java CLASSPATH directories. If this message is present,  complete the following steps:

1 - This class is stored in the xerces-1.2.3.jar archive file. Check if this this archive is present in the $CORE_ROOT/java/lib directory.

2 - If the installation procedure was successful, Integrator's CLASSPATH environmentvariable has a reference to this directory. Check that.

3 - If both previous conditions are met then augment the CLASSPATH variable with a reference to the xerces library jar file full path ($CORE_ROOT/java/lib/xerces-1.2.3.jar).

For information about how to update/modify an Integrator environment variable (e.g. CLASSPATH), refer to the official documentation of Integrator.