A schema cannot contain two global components with the same name
I am trying to validate a gml file using Xerces Java.
Then, I receive the below error message:
sch-props-correct.2: A schema cannot contain two global components with the same name; this schema contains two occurrences of 'http://www.opengis.net/gml/3.2,GeometricComplexType'.
systemid : http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19136_Schemas/geometryAggregates.xsd
Please guide me on how to eliminate the above error.

It sounds like you are
It sounds like you are including the same component twice.
See http://www.ogcnetwork.net/node/116 for possible solutions.
Also note that only the GML 3.2.1 gml.xsd is designed to validate.
Cheers,
kevin