SSMA warning message S2SS0016

SQL Server might use a different error code
                        Error code may change based on the Sybase and SQL Server for the same error.But in some cases both are having same error code.
                        Selecting the error from @@error and Returning error code by @@error wont make any difference in both the technologies.And generic condition check also wont make any difference.That means
     IF @@ERROR=0
     IF @@ERROR<>0
Both statement behaves same in sybase and SQL Server.We dont need to make any change for the below statement also.
SELECT @@ERROR
RETURN @@ERROR

If the script contains specific error code condition.Then we should take care of the error.
Please use the below links to refer Sybase error codes and meaning.

http://infocenter.sybase.com/archive/index.jsp?topic=/com.sybase.infocenter.dc36584.1260/html/iqerror/Errsybcode.htm

http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.39996_1250/html/svrtsg/svrtsg382.htm

http://manuals.sybase.com/onlinebooks/group-asarc/srv10024/errtsg/@Generic__BookTextView/77

According to the Sybase error codes change the equivalent SQL Server error codes in the Code.

Please click here to know about sybase to sql server migration issues