Вот код
Dim param As New System.Data.OracleClient.OracleParameter
Dim li As New listitem
SelectCommand.Parameters.Clear()
For Each variab As ListViewItem In lvspr.SelectedItems
var.idob = CType(variab.Text(), Integer)
Next
oracon.ConnectionString = var.constr
SelectCommand.Connection = oracon
oracon.Open()
SelectCommand.CommandType = CommandType.StoredProcedure
param = Me.SelectCommand.Parameters.Add("numobject", System.Data.OracleClient.OracleType.Number)
param.Direction = ParameterDirection.Input
param.Value = var.objname
param = Me.SelectCommand.Parameters.Add("idsybrnkref", System.Data.OracleClient.OracleType.Number)
param.Direction = ParameterDirection.Input
param.Value = var.idob
param = Me.SelectCommand.Parameters.Add("nameobject", System.Data.OracleClient.OracleType.Char, var.objname.Length)
param.Direction = ParameterDirection.Input
param.Value = var.objname
param = Me.SelectCommand.Parameters.Add("flag", System.Data.OracleClient.OracleType.Number)
param.Direction = ParameterDirection.InputOutput
param.Value = -1
SelectCommand.CommandText = "eac.p_object.set_object_to_tree"
SelectCommand.ExecuteNonQuery()

заголовок процедуры
PROCEDURE set_object_to_tree (
numobject IN NUMBER,
idsybrnkref IN NUMBER,
nameobject IN VARCHAR2,
flag IN OUT NUMBER
)

В результате возвращается ошибка "Input string is not correct format"
В чём проблема не пойму