Copy any .BAK and .LBK files out of C:\Program Files\Logbook Pro (or where you installed the software) to a safe location such as C:\Backup.
Uninstall
Reboot
Delete the Logbook Pro folder from C:\Program Files
Reinstall
Retry. If no luck, I'd have to point to something wrong with your Operating System. I highly recommend Windows XP. 98/Me are Microsoft's worst IMHO.