User '%1' already has EXECUTE permission

Item Value
SQLCODE -968
Constant SQLE_ALREADY_HAS_EXEC_PERMS
SQLSTATE 42WAB
Sybase error code 13522
ODBC 2 State 42000
ODBC 3 State 42000
Parameter 1 Name of the user ID that already has EXECUTE permission.

Probable cause 

You attempted to give a user EXECUTE permission on a stored procedure and that user already has EXECUTE permission on that procedure.