I have installed the latest j2sdk (b04) from /java/re/jdk/1.4.1/latest/bundles/win
(/net/koori.sfbay/p/v03/jdk/1.4.1/beta/b04/bundles/win)
using bundle j2sdk-1_4_1-beta-win.exe

If I bring up either Internet Explorer (5.50.4522.1800) or Netscape (6.2.1) and view a page with an applet (such as java.sun.com) and then at any point, whether still viewing the applet page or not, close the browser, I get an error dialog.

The dialog contains the title "Microsoft Visual C++ Runtime Library
The text is:

Runtime Error!
Program: C:\PROGRA~1\Plus!\MICROS~1\iexplore.exe
(or a similar path for Netscape)
R6025
- pure virtual function call

I have seen this problem on both my Windows NT machine and a Windows 2000 machine.