calling a stored procedure that runs textcopy, gives me errors

I have a stored procedure in my sql database:

CREATE PROCEDURE sp_textcopy (
@srvname varchar (30),
@login varchar (30),
@password varchar (30),
@dbname varchar (30),
@tbname varchar (30),
@colname varchar (30),
@filename varchar (30),
@whereclause varchar (40),
@direction char(1))
AS
DECLARE @exec_str varchar (255)
SELECT @exec_str =
'textcopy /S ' + @srvname +
' /U ' + @login +
' /P ' + @password +
' /D ' + @dbname +
' /T ' + @tbname +
' /C ' + @colname +
' /W "' + @whereclause +
'" /F ' + @filename +
' /' + @direction
EXEC master..xp_cmdshell @exec_str

i have been given the information but i need to call this procedure this is what i have been given:

sp_textcopy @srvname = 'ServerName',
@login = 'Login',
@password = 'Password',
@dbname = 'pubs',
@tbname = 'pub_info',
@colname = 'logo',
@filename = 'c:\picture.bmp',
@whereclause = " WHERE pub_id='0736' ",
@direction = 'I'

i haven't written a stored procedure call before.
how do you do it in vb.net.

i have tried this:

PHP Code:

---

        ' Create Instance of Connection and Command Object
        Dim myImageCommand As New SqlCommand()

        myImageCommand.Connection = myConnection
        myImageCommand.CommandType = CommandType.StoredProcedure
        myImageCommand.CommandText = "sp_textcopy"

        ' Add Parameters to SPROC
        'Dim FilePathName As String = (Server.MapPath((Session("username")) & ".jpg"))
        Dim objParam As SqlParameter

        ' server name
        objParam = myImageCommand.Parameters.Add("@srvname", SqlDbType.VarChar, 30)
        objParam.Direction = ParameterDirection.Input
        objParam.Value = "PC38"

        ' login user
        objParam = myImageCommand.Parameters.Add("@login", SqlDbType.VarChar, 30)
        objParam.Direction = ParameterDirection.Input
        objParam.Value = "RC"

        ' login password
        objParam = myImageCommand.Parameters.Add("@password", SqlDbType.VarChar, 30)
        objParam.Direction = ParameterDirection.Input
        objParam.Value = "ReportClient"

        ' database name
        objParam = myImageCommand.Parameters.Add("@dbname", SqlDbType.VarChar, 30)
        objParam.Direction = ParameterDirection.Input
        objParam.Value = "RunTime"

        ' table name
        objParam = myImageCommand.Parameters.Add("@tbname", SqlDbType.VarChar, 30)
        objParam.Direction = ParameterDirection.Input
        objParam.Value = "Person"

        ' colomn name
        objParam = myImageCommand.Parameters.Add("@colname", SqlDbType.VarChar, 30)
        objParam.Direction = ParameterDirection.Input
        objParam.Value = "PersonImage"

        ' filename
        objParam = myImageCommand.Parameters.Add("@filename", SqlDbType.VarChar, 30)
        objParam.Direction = ParameterDirection.Input
        objParam.Value = "c:\tma.jpeg"

        ' where clause
        objParam = myImageCommand.Parameters.Add("@whereclause", SqlDbType.VarChar, 40)
        objParam.Direction = ParameterDirection.Input
        objParam.Value = "WHERE PersonName=Session('username')"

        ' direction I=Input O=Output
        objParam = myImageCommand.Parameters.Add("@direction", SqlDbType.Char, 1)
        objParam.Direction = ParameterDirection.Input
        objParam.Value = "I"

        myConnection.Open()
        myImageCommand.ExecuteNonQuery()
        myConnection.Close() 


---

but i get this error:
xpsql.cpp: Error 997 from GetProxyAccount on line 499

or this one:
A severe error occurred on the current command. The results, if any, should be discarded

please help,
thanks
tom