After upgrade to ATG-7 patchset, User can't execute FND_GLOBAL.APPS_INITIALIZE

After upgrade to ATG-7 patchset, User can't execute FND_GLOBAL.APPS_INITIALIZE randomly.

He can't use distributed DB.

Bellow is the error message.  How to check it?

Error Msg:

java.sql.SQLException: ORA-20001: Oracle error -20001: ORA-20001: Oracle error -2074: ORA-02074: cannot SET NLS in a distributed transaction
has been detected in fnd_global.set_nls.set_parameter('NLS_LANGUAGE','AMERICAN').
has been detected in fnd_global.set_nls.
ORA-06512: at "APPS.APP_EXCEPTION", line 72
ORA-06512: at "APPS.FND_GLOBAL", line 245
ORA-06512: at "APPS.FND_GLOBAL", line 1426
ORA-06512: at "APPS.FND_GLOBAL", line 1684
ORA-06512: at "APPS.FND_GLOBAL", line 2309
ORA-06512: at "APPS.FND_GLOBAL", line 2447