I really recommend going through the kernel config (make menuconfig is easy to use) and doing your own configuration. Especially if you are using a distros stock kernel as your current kernel.
What is strange to me is even if you didn't compile in ext3 support ext3 partitions should be mountable as ext2 however the journal will not function. I would go through the entire kernel config, and among other things, carefully check what file systems are compiled in.
Also, you are passing in root=/dev/hda8 right? Another thing to consider, if you have a off board of second IDE controller on your motherboard the device ids can change depending on the kernel. For instance, I have a Promise Ultra 100 card on my system and depending on kernel options my first drive can either be /dev/hda or /dev/hde. Double check that. If it has reversed it from what it was before then you need to turn on (or off as the case may be) Boot Off-board chipsets first in the ATA section of the kernel configuration.