The error message when closing iCu2 is related to DirectX not being compatible with windows 98/Me:

You will most likely be set on  DirectX mode for your webcam on iCu2. Windows 98/Me doesn't like DirectX and produces an error (normally about vgcap.dll or kernel32.dll) when you close iCu2 if you are in DirectX mode.

You should be able to go into Tools - Options - Video, select "do not send video" then click on "change to VFW mode" button. Wait a moment for the cam list to appear, then select "Send Video From This Device".

If you continue to receive error messages or the camera does not appear when
in VFW mode, Please visit the webcam manufacturer's website and download/install the newest drivers for your webcam