I've had the same problem just a few days ago. It seems that you configured your ide or scsi support as a module instead of static into the kernel. When it tries to boot and you have them compiled as modules, you need aan initial ram disk.
The image then contains the necessary modules to boot your disks.
Other option: Also check if you configured the correct support for the filesystem. I only chose ext2 support, no extra attributes. After creating the image it gave me the size of it, and also mentioned : root filesystem (3,5). After installing that image i could boot.
Third option is to use the append option in the boot-loader.
append="root=x1x2" where x1 = major number in hex and x2 minor number of the root part.
In my case it was append="root=0305". But i solved it by compiling ide support static and only picking ext2 options (don't have ext3 so why compile
Hope this helps...