Too many arguments specified

I'm working with some Stored Procedures that have been encrypted. I've decrypted the stored procedures and I can see everything that is contained in the stored procedure. When I try and add new fields to the query in the SQL I keep receivin the following message:

[Microsoft][ODBC SQL Server Driver][SQL Server]Procedure or function sp_ShoppingGuide_GetArchivedRequestsByMAT2 has too many arguments specified.

I've added one more field and then renamed the Stored Procedure by adding a number 2 at the end. I've changed the name in my code, and the previous error is what I keep getting. Any insight on this? Thanks.

post the code in the procedure.

I've tried even just copying the same exact code and just renaming the stored procedure and i still receive the same error.

CREATE PROCEDURE sp_ShoppingGuide_GetArchivedRequestsByMAT
@UserID int = NULL,
@StartDate datetime,
@EndDate datetime,
@UnitID int = NULL
with encryption
AS
SET @UserID = CASE WHEN @UserID IS NULL THEN 0 ELSE @UserID END
SET @EndDate = @EndDate + 1
SET @UnitID = CASE WHEN @UnitID IS NULL THEN 0 ELSE @UnitID END
EXECUTE('
SET CONCAT_NULL_YIELDS_NULL OFF
SELECT
a.RequestID,
b.StatusID,
-- a.Archived,
-- a.DateArchived,
a.DateEntered,
a.Enteredby,
b.Quantity,
b.Comments,
c.ItemID,
c.ItemName,
c.CatalogNumber,
c.ServiceCode,
f.UnitName,
c.VendorName,
FullName = dbo.udf_Utils_FormatFullName(e.Lastname, e.Firstname, e.MiddleName)
FROM ShoppingGuide_Requests a
INNER JOIN ShoppingGuide_RequestDetails b ON (a.RequestID=b.RequestID AND b.StatusID=100)
LEFT JOIN ShoppingGuide_Items c ON b.ItemID=c.ItemID
LEFT JOIN Emp_UserJob d ON a.UserJobID=d.UserJobID
LEFT JOIN Emp_Users e ON (d.UserID=e.UserID)
LEFT JOIN Emp_Units f ON (d.UnitID=f.UnitID)
WHERE
(a.Enteredby=' + @UserID + ' OR ' + @UserID + '=0)
AND a.DateEntered BETWEEN ''' + @StartDate + ''' AND ''' + @EndDate + '''
AND (d.UnitID=' + @UnitID + ' OR ' + @UnitID + '=0)
ORDER BY a.RequestID DESC, c.ItemName
')