If you have more that one cdrom drive, try installing from the 2nd drive. Some cdrom drives have problems reading certain files when they start to go bad. Try cleaning the install cd.
Run a thorough scandisk in dos to ensure your hard drive does not have bad sector(s).
Since you haven't described your system I cannot say wether it's hardware related. Try disconnecting all of you un-necessary internal devices, leaving only those necessary to install (cpu/ram/video/hard drive/cdrom drive).
Let me know how it goes