> I'm confused how to continue.  Should IDE drives have hard read errors?
> (the other 4 I've installed didn't)

I'm much more familiar with SCSI than with IDE, but this is an instance where
the behavior is very likely the same.

Though it would seem very unlikely that a drive, any drive, would acquire
a hard error between being shipped from the factory and arriving on your
doorstep, it's not impossible.  All drives now manufactured (I think) have
automatic bad-sector remapping, but the trouble is that a drive only remaps
a sector when it knows what data should go there -- which generally means
it can only remap after a write error.  (I think some drives will remap on a
read if they successfully read the data past a certain point in the error-
recovery procedure.)  So, you probably need to run a program to specifically
ask your drive to remap bad sectors.  (Or you need to figure out how to get
badsect to work, but my inclination is to rely on the drive.)  I don't know
what kind of software comes with IDE controllers or drives; SCSI adapters
(and in the Mac world, SCSI drives) generally come with a formatter program
which can also scan for bad blocks and explicitly order a remap.  You may
have to format the entire drive if you haven't got such a scanning program
(or if you've completely abandoned DOS and can't run it if you have one);
the format process involves media certification and hard error spots get
added to the "grown defect" list (well, I don't know what that's called in
the IDE world, but I bet the disk drive's firmware source calls it that, since
the IDE code probably borrows from the ancestral SCSI code for that feature...
:-).

As to why badsect failed so bizarrely, I don't know.  The error message
certainly isn't very informative (oops, let's not open that can of worms
again... ;-).