First I've heard of something like that. I'm going to assume you've done this, but it has to be said; make sure that your discs aren't dirty or heavily scratched/scuffed.
That being said, if all else fails just download the client directly from the website. It'll take longer than just updating after installing from a hard copy, but you'll be able to avoid a "corrupted installer" issue more than likely.
Try copying the discs to your hard drive. If they wont copy there then there is a problem with them. if they do, try installing from there.
Depending on your broadband connection, it might just be quicker to download it as stated above.
Make sure you are an admin on the machine and running the installer in admin mode as well I guess.
www.repeat-offenders.net now playing GW2 with RO in Crystal Desert
RIP Sailor Rush, September 7th 2010.
http://www.change.org/petitions/ncsoft-keep-ncsoft-from-shutting-down-city-of-heroes
Sign the petition to save CoH please.
Thanks. Downloaded the client from Ncsoft website. Fixed my install troubles. 
Reloaded my Pc with Win7 During install of the game, just after I switch to the 2nd disk I get a corrupted installer failure. Never had this issue with Xp.