It happens not always but very often.

oCollection = CreateObject( "Shell.Application" )
?oCollection.Windows.Count      && let us say, 3
oIE = CreateObject("InternetExplorer.Application")
oIE.visible=.t.
?oCollection.Windows.Count     && 4

* at this point it happens with less frequency
?oCollection.Windows.Count     && ERROR, "class is not registered" ??

oIE.Navigate(.....)   && fine, it is here, no matter error occured or not

* at this point it happens with more frequency
?oCollection.Windows.Count     && ERROR, "class is not registered" ??

And I need to reboot the computer to use
?oCollection.Windows.Count
again.

Windows98 second edition, IE5.5, VFP6/7/8.

Thanks in advance for any comments.