Language Link in Masthead

Hi Exparts,

I am new to development in SAP.

We are using SAP Portal 7.3 EhP1 SP09.

I have imported the Masthead war file and I am trying to modify the Masthead.jsp.

I am trying to get the current user to change the user Locale language to/from English/Arabic.

I have seen many threads which discuss the same topic but could not full-fill my requirement.

I am using the below code to get the user :

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IUserMaint user = UMFactory.getUserFactory().getMutableUser(request.getUserPrincipal().getName());

But this is giving me exception: The given id "<userID>"is not a unique id of a user!]

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I have gone through the below links but no use.

http://scn.sap.com/thread/54206

http://scn.sap.com/thread/737677

http://scn.sap.com/people/michael.nicholls/blog/2006/09/27/let-a-user-change-their-portal-language-graphically

http://scn.sap.com/thread/2148440

http://scn.sap.com/thread/725261

Could someone please help me on this issue.

Thanks and Regards,

Visweswara Rao A.