I don't know how are you using the parameter
but this sholud helpyou going
Declare @str varchar(200)
SET @str = DB_NAME()--Assuming is going to be runned from other databases only
--otherwise use dbname as a parameter
+'.dbo.sp_helprolemember '
+ ''''
+ 'RoleName'
+ ''''
--print @str
exec (@str)
I don't know why can't the "plus" sign show