you gotta love SQL DateTime, check what is been sent to the database from your app, then check the format of the date in the database, most of the time you are sending MM/dd/yyyy while the database is expecting dd/MM/yyyy, try using collate or CONVERT for your dates, though until you see what is the app sending you will know better what to do
CONVERT(VARCHAR(10), GETDATE(), 101)
will make your date MM/DD/YYYY