Error Message In Calendar / Server Error In '/please-god' Application?

i am experiencing thi error when i click on the application in the remote machine.

Server Error in '/please-god' Application.

Security Exception Description: The application attempted to perform an operation not allowed by the security policy. To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file.

Exception Details: System.Security.SecurityException: Request for the permission of type 'System.Security.Permissions.EnvironmentPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

Source Error:

Line 7: Dim oBF As New BinaryFormatter()
Line 8: Dim oFS As FileStream
Line 9: Dim strPath As String = Path.GetTempPath & "schedule.Bin"
Line 10:
Line 11: Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

Source File: D:Hosting4423045htmlplease-godappointmentscheduler.aspx.vb Line: 9

the full codes for the application is this :

Imports System.IO
Imports System.Runtime.Serialization.Formatters.Binary

Partial Class appointmentscheduler
Inherits System.Web.UI.Page
Dim arrCalendar(12, 31) As String
Dim oBF As New BinaryFormatter()
Dim oFS As FileStream
Dim strPath As String = Path.GetTempPath & "schedule.Bin"
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If (Cache("arrCalendar") Is Nothing) Then
If (File.Exists(strPath)) Then
oFS = New FileStream(strPath, FileMode.Open)
arrCalendar = DirectCast(oBF.Deserialize(oFS), Array)
oFS.Close()
Cache("arrCalendar") = arrCalendar
End If
Else
arrCalendar = Cache("arrCalendar")
End If
End Sub
Protected Sub btnSave_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSave.Click
arrCalendar(Me.myCalendar.SelectedDate.Month, Me.myCalendar.SelectedDate.Day) = Me.myNotes.Text
oFS = New FileStream(strPath, FileMode.Create)
oBF.Serialize(oFS, arrCalendar)
oFS.Close()
Cache("arrCalendar") = arrCalendar
End Sub
Protected Sub btnDelete_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnDelete.Click
arrCalendar(Me.myCalendar.SelectedDate.Month, Me.myCalendar.SelectedDate.Day) = ""
oFS = New FileStream(strPath, FileMode.Create)
oBF.Serialize(oFS, arrCalendar)
oFS.Close()
Cache("arrCalendar") = arrCalendar
Me.myNotes.Text = ""
End Sub
Protected Sub myCalendar_DayRender(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DayRenderEventArgs) Handles myCalendar.DayRender
If arrCalendar(e.Day.Date.Month, e.Day.Date.Day) <> "" Then
e.Cell.BackColor = Drawing.Color.Red
End If
End Sub
Protected Sub myCalendar_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles myCalendar.SelectionChanged
Me.myNotes.Text = ""
If arrCalendar(Me.myCalendar.SelectedDate.Month, Me.myCalendar.SelectedDate.Day) <> "" Then
Me.myNotes.Text = arrCalendar(Me.myCalendar.SelectedDate.Month, Me.myCalendar.SelectedDate.Day)
End If
End Sub
End Class

What do i have to do to eliminate this error message?