Timeout waiting for DMA during boot ...

I've downloaded the 0.5.1-1 iso, and it fails with a "timeout waiting for DMA" during boot.  The iso MD5 checksum that I get agrees with what's posted here.  The last few trace lines are ...

hda: MWDMA2 mode selected
hdb: UDMA/66 mode selected
ide0 at 0x2020-0x2027-0x2016 on irq 23
ide1 at 0x2018-0x201f-02012 on irq 23
ide-cd driver 5.00
ide-cd hda: ATAPI 32x CD-ROM CD-R/RW drive 8192 cache
uniform CD-ROM driver revision: 3.20
ide-cd: hdb: ATAPI 48x DVD ROM DVD-R/RAM CD-R/RW drive 2048 cache
hdb: DMA timeout retry
hdb: timeout waiting for DMA

If I unplug the data cable for hdb, then the boot completes normally, and I can run GParted 0.5.1-1.
I can boot GParted 0.3.7-7 fine with all drives plugged in.

hda is a LG CD-RW CED-8120B; hdb is a  SONY DVD RW DRU-V200A

Does 0.5.1-1 not allow multiple CD / DVD drives to be plugged in?  Or is this a bug?