I had a disk that was partitioned like this: cyl begin cyl end type 1 651 /dos 654 2000 NetBSD (0xA9) I have free cylinders from 2000-8000 and by a typo, from 651 to 653. I try and make a 1024M / for Linux, (I have 3Gb free) and Diskdruid claims that I have no free disk space. Why? Because it only thinks that 651-653 is free. I fixed this in another window by expanding /dos to 653 (no file system in it yet), with fdisk, but there is no way to convince the install to reload the partition table from the raw disk, so I have to reboot. It would also be nice if "fdisk" could print the entire name of the partition type in "L". Also if it knew about 0xA8 FreeBSD, 0xA9 NetBSD.
Unless you have a /boot partition, the / partition must reside under cylinder 1024 due to BIOS limitations (nothing to do with Linux). So disk druid was trying to put it in the only valid free chunk available. In your case I would make a /boot of about 30 megs under the 1024 cylinder limit, and then you can put / anywhere.