The first exception is saying that you're accing a control object from a
thread other than that it was created in. VS 2003 doesn't give this warning,
unfortunately, you just get odd behaviour. Don't know what the second one's
about. Post some minimal code that reproduces the behaviour.

Steve

Situation:
A worker thread calls a method in the UI thread (or raises an event in
the UI thread)

In 2003 it was possible to update UI controls directly from the called
methods.

2005 throws an error:

Illegal cross-thread operation: Control 'StatusBarPanel1' accessed
from a thread other than the thread it was created on.

Solution:

Public Sub ThreadFeedback(ByVal sender As Object, ByVal e As
ThreadEventArgs) Implements IAsynchThread.ThreadFeedback
   'Tell calling worker thread whether to cancel operation
   e.Cancel = _Cancel
   'Call UI thread asynchronously (and thus thread save)
   Dim pList As Object() = {sender, e}
   Me.BeginInvoke(New System.EventHandler(AddressOf UpdateUI), pList)
   Application.DoEvents()
End Sub

Private Sub UpdateUI(ByVal sender As Object, ByVal e As
System.EventArgs)
   'Do all the UI thread relevant stuff here
   'e.g. update StatusBar panel text etc.
   Dim ef As ThreadEventArgs = CType(e, ThreadEventArgs)
   StatusBarPanel1.Text = ef.Text
End Sub

'Remarks:
'IAsynchThread is an Interface of my own
'ThreadEventArgs is a Class of my own
'_Cancel is a UI module level variable that is set to True
'when the user clicks on the Cancel button.

Reason:
The UI controls are not thread safe. Previous versions of .Net would
allow these thread-unsafe to be made, but they will cause weird things
to happen (often resulting in the application just disappearing)
eventually. .Net 2 detects these bad cross-thread calls, and raises an
exception.

When in another thread, you should invoke all UI control methods using
BeginInvoke and EndInvoke rather than directly.