replacement UJ-875S reading only DVDs not CDs

I've just replaced my dead UJ-816-C with a UJ-875S superdrive. The drive is reading DVDs fine, but will not read CDs of any type. Oddly enough it will accept a blank CDR and burn to it. However, it rejects blank DVD-R media. I get the typical sounds of it trying to read and then it ejects the disc. I have gone though all the typical system resets (PRAM, caches, etc.) with no difference resulting. Likewise, I have tried the firmware DATs posted on rpc1.org for this drive. Any other ideas?

Here are the details from the system profiler:

MATSHITA DVD-RAM UJ-875S:

Firmware Revision: 1.01

Interconnect: ATAPI

Burn Support: Yes (Unsupported)

Profile Path: None

Cache: 2048 KB

Reads DVD: Yes

CD-Write: -R, -RW

DVD-Write: -R, -RAM, -RW, +R, +RW, +R DL

Burn Underrun Protection CD: Yes

Burn Underrun Protection DVD: Yes

Write Strategies: CD-TAO, CD-SAO, DVD-DAO

System Software Overview:

System Version: Mac OS X 10.4.11 (8S165)

Kernel Version: Darwin 8.11.0