I believe that the UDF volume of this disc is left in an inconsistent state due to the unfortunate computer freeze.
I suggest to use the powerful isobuster to attempt to recover your data. More info at http://www.smart-projects.net/framepage.htm?http://www.smart-projects.net/isobuster.htm
Notice that if you are able to reproduce the freeze, you may issue an helpful bug report by using the following steps:
1. Save all important data that resides on the test computer.
2. Please, check that you have enough hard disk free space to save memory dump. It should be at least 1Mb bigger than size of the RAM.
3. Setup Windows XP to generate a complete memory dump (in system properties, advanced tab, startup and recovery, write debugging information).
4. Reboot the PC.
5. Run RegEdit.exe
6. In the Registry key HKEY_LOCAL_MACHINE\System\ CurrentControlSet\Services\i8042prt\Parameters, find or create a DWORD value named CrashOnCtrlScroll. Double-click on the value and set its data to 1.
7. Restart your computer again.
8. Now you can cause a crash by holding the right-hand Ctrl key and pressing the Scroll Lock key twice. [Reproduce the defect and] Do it. The computer will reboot. It is normal.
9. Boot computer again and wait ~10 minutes for crash dump generation by the OS.
10. Please, do not send the information to Microsoft, i.e. press “Don’t send” button if dialog shown on the screenshot below appears.
11. Find memory.dmp file in your system root folder (for example C:\Windows).
12. Archive the memory.dmp file and upload it on an FTP server (the file will likely be huge).
I recommend against using this procedure on any production system(!).