Using of schemavalidate returns an unexpected error

I experience something strange to me and I am open to any commentary helping me to solve my problem.

I am using dbms_xmldom to create xml file in PL/SQL.

Let's say I have created such a document named "doc" with this. I write it down to a file with this :

dbms_xmldom.writeToFile(doc,'docFile', 'UTF-8');
v_xml:=DBMS_XMLDOM.GETXMLTYPE(doc);
dbms_xmldom.freeDocument(doc);

I would like to validate this document. Here we go :

v_schema:=v_xml.createSchemaBasedXML('myValidationFile.xsd');
v_schema.schemavalidate();

Here I have this error :

ORA-31154: invalid XML document
ORA-19202: Error occurred in XML processing
LSX-00249: invalid date or time "2015-01-07T15:20:41,000000"

Looking at my file called 'docFile' I just see 2015-01-07T15:20:41. I dont know where this ',000000' comes from.

This has always worked before but I am testing a platform with Oracle 11 now (before it was Oracle 10). I dont know if this has something to do with it but I am telling anyway.

Thanks for the suggestions