com.dwl.base.requestHandler.exception.RequestParserException: [Exception_myErrorHandler_SAXParseError:] The parsing of the XML failed at the following position

I had did an extension on the grouping table to add XMyExtId .
When I ran the addGrouping trasaction with the extended field I got the following response.

Parser DWLTransaction failed. The format of the message is not correct or an application error occurred.
com.dwl.base.requestHandler.exception.RequestParserException: [Exception_myErrorHandler_SAXParseError:] The parsing of the XML failed at the following position. XML = org.xml.sax.SAXParseException: Element type "XMyExtId" must not be declared more than once.; line number = 64; column number = 34


The reason being I had already done an entity addition which is having the attribute XMyExtId .Even if entries for grouping extension goes to DWLrequest_extesnion.dtd & repsonse ,during the parsing it still looks at the trcrmrequest_extsnsion.dtd(I dont know the reason for that) whcih is having the entry XMyExtId for my addition  I did earlier.

Solution:

Just rename the attribute XMyExtId you used for extension or else you can utilize the old deceleration for XMyExtId by commenting out the current one.