Sub Main()
' Get the main system object
  Dim Sessions As Object
  Dim System As Object
  Set System = CreateObject("EXTRA.System")
  Set Sessions = System.Sessions

' Get the necessary Session Object
  Dim Sess0 As Object
  Set Sess0 = System.ActiveSession
  If (Sess0 is Nothing) Then
  STOP
  End If
  If Not Sess0.Visible Then Sess0.Visible = TRUE
  Sess0.Screen.WaitHostQuiet(g_HostSettleTime)

'---------------------------------------------------

'obtains data from the first screen and takes action based on data

  Dim variable1 As Object
  Set variable1 = Sess0.Screen.area(row1,col1,row2,col2)
  Select case variable1
      case "something"
         'sends a keystroke which makes it go to the next screen
         Sess0.Screen.Sendkeys("<pf6>")
         'gets data from next screen....this is where my code doesn't want to work
         Dim screen2variable As Object
         Set screen2variable = Sess0.Screen.area(row1,col1,row2,col2)
         'takes action based on data from screen 2
         Select Case screen2variable
         case "something2"
           Sess0.Screen.MoveTo row1,col1
           Sess0,screen.SendKeys("writesomething<Enter>")
           Stop
         Case "alternative"
           Stop"   
         End Select

      Case "something_else"  
         'takes a different action  
         Sess0.screen.Sendkeys("<pf8>")
         Stop
  
  End Select
End Sub

Sess0.Screen.Sendkeys("<pf6>")
Do you need a wait here? I would guess your code is proceeding before the new screen loads and running into the the case with "Stop".
Dim screen2variable As Object

Function WaitForScreenChange
    strOld=objScreen.area(1,1,24,80,,3)
    strNew = strOld
    objScreen.SendKeys("<pf6>")
    For i = 0 to 500
        strNew=objScreen.area(1,1,24,80,,3)
        if strOld<>strNew then Exit For
        Do Events
    Next
    If i > 499 then
        objScreen.WaitHostQuiet(1000)
        strNew=objScreen.area(1,1,24,80,,3)
    End If
    WaitForScreenChange = strNew
End Function