First please confirm that you have the right kind of OEM version - only the "System Builder's OEM" or a full retail version of XP SP2 will work in boot camp (I assume you are referring to a boot camp installation although you didn't specify). If you are using the OEM disk from a computer vendor, such as Dell, HP, Gateway, Sony, etc., or a volume-licensed version of XP, those will not work and will produce errors.
If that's what you have, you'll need to purchase a System Builder's OEM version or full retail version. The only difference between the two is the licensing terms; the SBOEM version can only be used on one computer, ever. the full retail version can be used on multiple computers but only one at a time.
Cheers