Stored procedure with output parameter in sql server

CREATE TABLE [dbo].[userinformation](

      [Uid] [int] IDENTITY(1,1) PRIMARY KEY,

      [UserName] [varchar](50) NULL,

      [Password] [varchar](50) NULL,

      [FirstName] [varchar](50) NULL,

      [LastName] [varchar](50) NULL,

      [Email] [varchar](50) NULL,

      [PhoneNo] [varchar](50) NULL,

      [Location] [varchar](50) NULL,

      [CreatedBy] [varchar](50) NULL,

      [Error] [varchar](50) NULL

      )

CREATE proc [dbo].[sp_userinformation]

(

@UserName varchar(20),

@Password varchar(20),

@FirstName varchar(20),

@LastName varchar(20),

@Email varchar(20),

@PhoneNo varchar(20),

@Location varchar(20),

@CreatedBy varchar(20),

@ERROR VARCHAR(30) OUT

)

AS

BEGIN

SET NOCOUNT ON;

if not exists(select *from userinformation where UserName=@UserName)

begin

INSERT INTO userinformation (UserName,Password,FirstName,LastName,Email,PhoneNo,Location,CreatedBy)values(@UserName,@Password,@FirstName,@LastName,@Email,@PhoneNo,@Location,@CreatedBy)

set @ERROR=@UserName + 'Registered Successfully'

END

else

set @ERROR=@UserName + 'Already exists'

end

protected void btnsubmit_Click(object sender, EventArgs e)

    {

        string message = "";

        if (txtpwd.Text == txtcnmpwd.Text)

        {

            cmd = new SqlCommand("sp_userinformation", con);

            cmd.CommandType = CommandType.StoredProcedure;

            cmd.Parameters.AddWithValue("@UserName", txtuser.Text);

            cmd.Parameters.AddWithValue("@Password ", txtpwd.Text);

            cmd.Parameters.AddWithValue("@FirstName", txtfname.Text);

            cmd.Parameters.AddWithValue("@LastName", txtlname.Text);

            cmd.Parameters.AddWithValue("@Email", txtEmail.Text);

            cmd.Parameters.AddWithValue("@PhoneNo", txtphone.Text);

            cmd.Parameters.AddWithValue("@Location", txtlocation.Text);

            cmd.Parameters.AddWithValue("@CreatedBy", txtuser.Text);

            cmd.Parameters.Add("@ERROR", SqlDbType.Char, 30);

            cmd.Parameters["@ERROR"].Direction = ParameterDirection.Output;

            con.Open();

            cmd.ExecuteNonQuery();

            message = (string)cmd.Parameters["@ERROR"].Value;

            con.Close();

        }

        else

        {

            Page.RegisterStartupScript("UserMsg", "<Script language='javascript'>alert('" + "Password mismatch" + "');</script>");

        }

        lblErrorMsg.Text = message;

    }

<table align="center">

<tr>

<td></td>

<td align="right" >

</td>

<td align="center">

<b>Registration Form</b>

</td>

</tr>

<tr>

<td></td>

<td align="right" >

<asp:Label ID="lbluser" runat="server" Text="Username"></asp:Label>

</td>

<td>

<asp:TextBox ID="txtuser" runat="server"></asp:TextBox>

</td>

</tr>

<tr>

<td></td>

<td align="right" >

<asp:Label ID="lblpwd" runat="server" Text="Password"></asp:Label>

</td>

<td>

<asp:TextBox ID="txtpwd" runat="server" TextMode="Password"></asp:TextBox>

</td>

</tr>

<tr>

<td></td>

<td align="right" >

<asp:Label ID="lblcnfmpwd" runat="server" Text="Confirm Password"></asp:Label>

</td>

<td>

<asp:TextBox ID="txtcnmpwd" runat="server" TextMode="Password"></asp:TextBox>

</td>

</tr>

<tr>

<td></td>

<td align="right">

<asp:Label ID="lblfname" runat="server" Text="FirstName"></asp:Label>

</td>

<td>

<asp:TextBox ID="txtfname" runat="server"></asp:TextBox>

</td>

</tr>

<tr>

<td></td>

<td align="right">

<asp:Label ID="lbllname" runat="server" Text="LastName"></asp:Label>

</td>

<td>

<asp:TextBox ID="txtlname" runat="server"></asp:TextBox>

</td>

</tr>

<tr>

<td></td>

<td align="right">

<asp:Label ID="lblemail" runat="server" Text="Email"></asp:Label>

</td>

<td>

<asp:TextBox ID="txtEmail" runat="server"></asp:TextBox>

</td>

</tr>

<tr>

<td></td>

<td align="right" >

<asp:Label ID="lblCnt" runat="server" Text="Phone No"></asp:Label>

</td>

<td>

<asp:TextBox ID="txtphone" runat="server"></asp:TextBox>

</td>

</tr>

<tr>

<td></td>

<td align="right" >

<asp:Label ID="lbladd" runat="server" Text="Location"></asp:Label>

</td>

<td align="left">

<asp:TextBox ID="txtlocation" runat="server"></asp:TextBox>

</td>

</tr>

<tr>

<td>&nbsp;</td>

<td align="right" >

    &nbsp;</td>

<td align="left">

    &nbsp;</td>

</tr>

<tr>

<td></td>

<td></td>

<td align="left" ><asp:Button ID="btnsubmit" runat="server" Text="Save"

onclick="btnsubmit_Click" />

<input type="reset" value="Reset" />

</td>

</tr>

<tr>

<td></td>

<td></td>

<td>

<span style= "color:Red; font-weight :bold"> <asp:Label ID="lblErrorMsg" runat="server"></asp:Label></span>

</td>

</tr>

</table>