Invalid return value when using ExecuteNonQuery ()

I have a C # program that I am writing that interacts with SQL Server. I stupidly encoded the query strings in a C # program and wanted to include them in the stored procedures on the server instead.

For some reason, one particular INSERT statement (which works fine!) No longer works, and I can't figure out why. I even run SQL Profiler Trace, and it shows that the statement is perfectly formed! Maybe someone can tell me what I'm doing wrong.

REMEMBERED PROCEDURE: This SP simply takes a set of parameters and inserts them into the table. Very simple.

ALTER PROCEDURE [dbo].[usp_InsertNewChangeRequest]

@Requester INT,
@ChangeCreationDate DATETIME,
@ChangeName VARCHAR(200),
@ChangeDescription VARCHAR(1000),
@LastModifiedDate DATETIME,
@LastModifiedBy INT,
@AffectedArea INT,
@ImplementationPlan VARCHAR(MAX),
@BackoutPlan VARCHAR(MAX),
@RiskLevel TINYINT,
@ApprovalRequired BIT,
@IsApproved BIT
AS
BEGIN
SET NOCOUNT ON;

INSERT INTO dbo.ChangeRequests(Requester, ChangeCreationDate, ChangeName, ChangeDescription, 
            LastModifiedDate, LastModifiedBy, AffectedArea, ImplementationPlan, BackoutPlan, 
            RiskLevel, ApprovalRequired, IsApproved)
VALUES (@Requester, @ChangeCreationDate, @ChangeName, @ChangeDescription,
            @LastModifiedDate, @LastModifiedBy, @AffectedArea, @ImplementationPlan, @BackoutPlan,
            @RiskLevel, @ApprovalRequired, @IsApproved) 
END

My code in C # simply adjusts the SP parameters and then calls the request:

public int InsertNewChange(int RequesterID, DateTime CreationDate, string ChangeName,
        string ChangeDescription, DateTime LastModifiedDate, 
        int AffectedAreaID, string ImplementationPlan, string BackoutPlan,
        int RiskLevel, int ApprovalRequired, int IsApproved)
    {
        int retval = 0;

        // Create a command whose name is the stored procedure for inserts
        SqlCommand command = new SqlCommand("usp_InsertNewChangeRequest", scConnection);
        command.CommandType = CommandType.StoredProcedure;

        // add the parameters to the stored procedure
        command.Parameters.Add(new SqlParameter("@Requester", RequesterID));
        command.Parameters.Add(new SqlParameter("@ChangeCreationDate", CreationDate));
        command.Parameters.Add(new SqlParameter("@ChangeName", ChangeName));
        command.Parameters.Add(new SqlParameter("@ChangeDescription", ChangeDescription));
        command.Parameters.Add(new SqlParameter("@LastModifiedDate", LastModifiedDate));
        command.Parameters.Add(new SqlParameter("@LastModifiedBy", RequesterID));
        command.Parameters.Add(new SqlParameter("@AffectedArea", AffectedAreaID));
        command.Parameters.Add(new SqlParameter("@ImplementationPlan", ImplementationPlan));
        command.Parameters.Add(new SqlParameter("@BackoutPlan", BackoutPlan));
        command.Parameters.Add(new SqlParameter("@RiskLevel", RiskLevel));
        command.Parameters.Add(new SqlParameter("@ApprovalRequired", ApprovalRequired));
        command.Parameters.Add(new SqlParameter("@IsApproved", IsApproved));

        retval = command.ExecuteNonQuery();
        return retval;
    }

-1, , SQL, #, 1, 1 .

, SQL Profiler . , , ! Management Studio , .

    exec usp_InsertNewChangeRequest @Requester=4,@ChangeCreationDate='2012-05-16 17:55:45',@ChangeName='test name',@ChangeDescription='test description',@LastModifiedDate='2012-05-16 17:56:01.937',@LastModifiedBy=4,@AffectedArea=2,@ImplementationPlan='test implem',@BackoutPlan='test backout',@RiskLevel=1,@ApprovalRequired=0,@IsApproved=0

- , ? !