Side-by-Side Partitions - Both Don't Boot

[busydog]

Thanks in advance for you help...

I have a 120 gig Fujitsu HD on a MacBook running 10.5.4.
The first partition is 79.9 gig with 60.7 gig available. The format is Mac OS Extended (Journaled), Partition Number 2 -- I can boot to it successfully.
The second partition is 31.5 gig and has almost 12.5 gig available. The format is Mac OS Extended (Journaled), Partition Number 3 -- That is not bootable using the Option Key

The only difference I can see from Disk Utility (within Leopard) is that the first partition mountpoint is / and the second is /Volumes/Backup

I created the second partition using BootCamp and then reformatted it using Disk Utility. I guess I could have bought iPartition and done the reformatting that way but this looks like it was the easy way to go.