Have you tryed sfdisk? That's what i use instead of cfdisk.
Assuming you only want two partitions to use, try this in x-term:

First, run "apt-get -f install e2fsprogs" However if you are using Diablo, you may not need this step.

Next, run "sfdisk -uM /dev/mmcblk1p2", this will allow you to partition in mb units.

now put ",40,6" This marks the first partition as 40 mb with a fat 16 format

next put ",,L" This allows the rest of the memoy card to use linux83 for your os.

the last two would just be ",," witch marks them as empty and if the reloading of the partition tables fails, just reboot and skip the partitioning alltogether and simply mount/format your partition.