Cannt read II.Session on DVD-R-Medium

Hello there!
Does anyone has an idea, why i cannot read my second session on a DTK-DVD-R drive? I wrote with NeroExpress on WinXP. Nero burned successfully, IsoBuster shows all Session. BUT: in Explorer on WinXP SP2, i cannot see the second session. I use Plextor PX-708A with the newest firmeware. Where shall i search for the solution.

use your dvd burner to read multisession dvd-r.

On my system, I have to eject, then insert the disc to see the session that I have added. Refreshing explorer does not work.