empeg:/empeg/bin# dd if=/dev/hda3 of=/dev/null bs=512
48194+0 records in
48194+0 records out
Your dynamic partition is 24Mb instead of the normal 16Mb. How did that happen? Did you fdisk this disk yourself, instead of with a builder image? What does "fdisk -l /dev/hda" say?

Here's what it says on a standard disk: 
empeg:/empeg/bin# fdisk -l /dev/hda



Disk /dev/hda: 16 heads, 63 sectors, 38760 cylinders

Units = cylinders of 1008 * 512 bytes



   Device Boot    Start       End    Blocks   Id  System

/dev/hda1             1        66     33232+   5  Extended

/dev/hda2            67       132     33264   83  Linux

/dev/hda3           133       165     16632   10  OPUS

/dev/hda4           166     38760 19451880   83  Linux

/dev/hda5             1        33     16569   83  Linux

/dev/hda6            34        66     16600+  82  Linux swap
Clearly the number in bold is going to be different on different-sized disks, but the rest of the block sizes should be just about the same (and, if your cylinders are the same size as mine, exactly the same).

Peter