Unable to execute stored procedure

Question

Hello everybody..

I have this stored procedure running over SQL Server express 2005:

ALTER PROCEDURE dbo.ShowBooksResForEachShop(@BookBarcode nvarchar(25), @DateFrom datetime)

AS

   Select Shop.name, Reservation.amount

   From Shop,Reservation

   Where Reservation.shopNum = Shop.num AND Reservation.barCode = @BookBarcode AND           Reservation.date >  @DateFrom

RETURN

When I'm trying to execute (  dbo.ShowBooksResForEachShop ('3220618',  1/ 1/ 1888 )  ) it I'm getting the following error: 

Incorrect syntax near '3220618'

The weird thing is that the procedure work great when I'm executing it with the "Run stored procedure" VS tool.

Can someone help me figure what I'm doing wrong?

Thanks in advance,

Lior..