I am attempting to triple boot Ubuntu, Windows 7, and Backtrack 4. Win7 and Ubuntu are both booting and working properly, but after trying a number of configurations for GRUB I cannot boot Backtrack. Everything I attempt seems to come back to one problem and result in the same error: Error 17.

sda contains both my Windows and Ubuntu partitions...

Code:
Disk /dev/sda: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x07dccf10

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1       12748   102398278+  83  Linux
/dev/sda2   *       12749       29272   132729030    7  HPFS/NTFS
/dev/sda3           29273       30401     9068692+   5  Extended
/dev/sda5           29273       30401     9068661   82  Linux swap / Solaris
...while sdd contains the Backtrack partition.

Code:
Disk /dev/sdd: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x97acc7fc

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1        9327    74919096   83  Linux
/dev/sdd2            9328        9729     3229065    5  Extended
/dev/sdd5            9328        9729     3229033+  82  Linux swap / Solaris
Can anybody point me in the right direction to getting sdd mounted? Is it even possible to boot from a separate hard disk the way I am attempting to? I know chainloading is a method typically used for unsupported operating systems, but is this a situation where it should be used?