Python Script Set Dataset permission Error

I try to run Python scrip(10.1) to set network dataset permission but get error.does anyone know why?

here is the Python code:arcpy.ChangePrivileges_management(targetDBConn +"Transportation",
"GISVEC1_APP_RL", "GRANT", "GRANT")

Here is the error message:ERROR 999999: Error executing function.
Underlying DBMS error [Microsoft SQL Server Native Client 10.0: Incorrect syntax near '-'.]
Failed to execute (ChangePrivileges).

Thanks.