When invoking the 2.1i Design Manager under SunOS 5.6 (Solaris 2.6), the following warning and error appears:
Wind/U Warning (240): Unknown locale specified locale: LANGUAGE:UNDEFINED SUBLANGUAGE: X Error: BadValue Request Major code 91 () Value 0xff Error Serial #17 Current Serial #17
The first Warning (240) can be safely ignored, however for more information on it, please reference (Xilinx Solution 4563).
The particular case where the "X Error" occurs can be resolved by re-installing the tools and following the Installation Procedure as documented in the Install and Release Documentation.
NOTE: Make sure the environment variable LD_BREADTH=1 is set.
In one particular case where the above error appeared, the fix involved changing all Xilinx files to be owned by the specific user (due to permissions conflicts), since the user was not in the same group as the original owner of the files.