Hm, I have an Asus P5E and have installed all of the drivers
from the Asus site (for both Windows 7 x32 and x64) several times and never had an issue.
I assume you are running Windows 7 32-bit, correct? Do you have the latest BIOS updated 1101? If not, I would update that first, then download and install the latest chipset drivers*, then install the sata drivers.
* Sometimes, to get Windows 7 to install the chipset drivers, you have to run the downloaded exe from the command line with the following "<chipsetname>.exe -override -overall". If you just double click the exe to install them all, Windows 7 will sometimes say "no thanks, the ones I have are fine" and not actually update them all.