Parameter Conversions Question From SQL Server

I have a question regarding a casting error I recieve when I explictly assign a value to a value in a stored procedure.......


The value pstrLoginName is a public string defined in a code module


The stored procedure is NVARCHAR Datatypes.....





Here is the Stored Procedure





CREATE procedure dbo.Appt_GetPermissions_NET


(


@LoginName nvarchar(15),


@Password NvarChar(15),


@DeleteScan bit Output





)


as


select





@DeleteScan=UserP_DeleteScan


from


Clinic_Users


where


UserName = @LoginName


and


UserPassword = @Password





GO








Here is my error





Specified cast is not valid


Line 194: cmdsql.CommandType = CommandType.StoredProcedure


Line 195:


Line 196: parmLogin = cmdsql.Parameters.Add("@LoginName", SqlDbType.NVarChar, 15).Value = pstrLoginName


Line 197: parmPassword = cmdsql.Parameters.Add("@LoginPassword", SqlDbType.NVarChar, 15).Value = pstrLoginPassword


Line 198: parmDelete = cmdsql.Parameters.Add("@DeleteScan", SqlDbType.Bit)





my vb .net code to execute this





Public Sub ObtainPermission()








'get the needed data


Dim consql As New SqlConnection("Server=myserver;database=APPOINTMENTS;uid=webtest;pwd=webtest")


Dim cmdsql As New SqlCommand


Dim parmLogin As SqlParameter


Dim parmPassword As SqlParameter


Dim parmDelete As SqlParameter





cmdsql = New SqlCommand("Appt_GetPermissions_NET", consql)


cmdsql.CommandType = CommandType.StoredProcedure





parmLogin = cmdsql.Parameters.Add("@LoginName", SqlDbType.NVarChar, 15).Value = pstrLoginName <----error occurs here





parmPassword = cmdsql.Parameters.Add("@LoginPassword", SqlDbType.NVarChar, 15).Value = pstrLoginPassword <---I'm sure it will happen here then


parmDelete = cmdsql.Parameters.Add("@DeleteScan", SqlDbType.Bit)


parmDelete.Direction = ParameterDirection.Output





consql.Open()


cmdsql.ExecuteNonQuery()





'obtain rights





pstrPermissions = cmdsql.Parameters("@DeleteScan").Value


consql.Close()





End Sub