I agree- start with cleaning the disks.
mrjamin
CDRWs have a limited life time (mind you, as do regular CD-ROMs, but theirs is significantly longer...
From somebody that works with a lot of DVDs and CDs: The statistic was somewhere around 11 years of constant reading before a normal pressed CD would experience significant data loss. For CDRs/RW it is faster, but simple storage and normal use shouldn't degrade the disk significantly. Disks with a faster burn time, i.e. "Record at up to 40x" have dyes that are more sensitive to radiation and disks with slower burn in times "..12x,8,4,2,1" have less sensitive inks. Leaving a disk out in the sun can cause permanent erasure and data loss. Also, some disks are susceptible to data loss when frozen, as the disk is a compost, the sandwiched materials can delaminate under extreme thermal strain. Some other possible reasons for failure is incompatible format (usually not a problem for a Mac), lack of a catalog track, incomplete burn in, poor/failed burn in or poor/failed read due to burner problems. Burners/readers do have life spans. If you burn a lot of disks, you might of burnt out the laser diode, or there might be some other problem with either the burn in drive or the drive your using to read the disks.
Some of the equipment that I have at works. I have several Mac/PC DVDrw/CDrw FantomDrives (Mostly to burn 9.2Gb type I cartraages), 2 MO drives (not worth the cost and time to burn), dozens of CD burners, and we will have a mass CD duplicator (robot arms just look so cool when working) in house with in the next year. I have the unfortunate task of to compress over 1000gB of nearly uncompressible data from 3 SnapServers and move it to a new archive later this month. My boss wants me to use DVDs, another CDs, and new equipment is just out of the question. Sorry- I needed to vent.
