This problem is reported by Starwood, running a FVB based on 5.0u9/10 workspace.
(currently tracked under escalation 1-19151929)

This crash is not reproduced with 5.0u9 /net/jre.sfbay/p/v05/jdk/1.5.0_09/fcs/b01/bundles/windows-i586/jre-1_5_0_09-windows-i586-p.exe

but is reproducible with 5.0u10
/net/jre.sfbay/p/v05/jdk/1.5.0_10/ea/b01/bundles/windows-i586/jre-1_5_0_09-ea-windows-i586-p.exe

so it is very likely that this is a regression in 5.0u10

Here's the steps involved:

1. Log on to http://10.5.20.148:8080/lightspeed?overridejvm=true
 user: 1200 pass: summer
2. you will be at the arrival screen, (combo box showing "Arrivals")
 select a guest entry:
 single click on the "Soderstrom, Marcianna....." entry
3. select the "Rate Sched BAR10" link at the top
4. a popup window comes up, select the "close" button
5. select the guest entry again (single click)
6. IE crash (repeat steps 3-5 if necessary to crash IE)

There is a full dr watson dump collected with the above 5.0u10 run in
/net/cores.central/cores/dir31/64990026/0918