setup.exe - Bad Image while installing win 7

First the exact situation and background:

While I was installing an OEM 64-bit version of Windows 7 I got the following pop-up message during the "completing installation" step:

setup.exe - Bad image
C:\Windows\system32\sppc.dll is either not designed to run on windows or it contains a error. Try installing the program again using the original installation media or contact your system administrator or the software vendor for support.

I hit ok, and it popped up again... and again... etc.
So finally I tried to cancel the Install via the standard red x routine. Upon which i received a message saying that installation cannot be cancelled at this point... blah blah"

So being stuck and unable to finish or cancel the installation, I went for the good old turn off the computer method.
Then I started fresh reformatting the drive and all. I had to leave the location I was at unfortunately while it was at "extracting files 52%" We'll see what's showing when I arrive in the morning.

Now, the question(s):

What causes this message to appear? And obviously, how do I fix/prevent it?

If it's due to bad media, how do I get a replacement copy? (seeing as it's OEM and thus I am technically responsible for support as I am the system builder)

Finally, the disclaimer:

Yes, I do know the difference between OEM and Retail. Yes, I did legitimately purchase the installation media & key. Yes, I am reselling this system to an end user; it is NOT for personal use. No, I did not run the OPK prior to using this software; I did not see the point as in this particular case I am personally setting up the machine for the client (plugging it in, installing software, registering & activating that software as well as the OS, etc.) Yes, I did look on this forum, as well as others, including window's own, and all over "the Google" to no avail, I've yet to find anything helpful.

Thanks In Advance,
quiznos

p.s. sorry if the disclaimer section seems a bit harsh but I've seen a number of questions on various sites where people get asked about the legalities or get pointed to an irrelevant thread/forum/blog and never get their answer. I simply don't want to be one of those people. However, theories and relevant questions are welcome. (unless your theory is that it's because I eat too many Cheetos, I already know THAT'S a problem)

How are you installing exactly? DVD, flash stick, image?

If it was a new HD then it could really only be installer error resulting from bad ISO or burn.

Verify the installer's integrity by downloading another ISO if you did, burning at 4x speed with ImgBurn with Verify, or writing ISO to flash stick with this tool: Universal USB Installer – Easy as 1 2 3

On retry did you boot the installer to choose Custom Install, then using Drive Options to delete all partitions, create New, Format before install?

You may need to wipe the HD of all code against possible boot sector corruption.

Installing via DVD disk. Sorry, forgot to mention that.
First time, when I had the issue, I did Custom Install, selected each partition that was there (HD from old xp system) and deleted them, then clicked "new" and continued as usual.
Second time, formatted each partition, deleted each partition, "new", formatted again. But I've yet to see the result from this.

The reason Io put "new" in quotes is because it actually creates 2 partitions System, and Primary on which I've been installing onto the primary partition.

EDIT: I've done this before with retail copies with no issue. It's never seemed to make a difference whether I zeroed out the respective HDDs or not before the installation.

I looked at your link "perfect reinstall," which is helpful on its own, and now I'm wondering... Could install the operating system via a retail disc I have (but has been previously used/activated/registered), and know works, and then use the COA key from the OEM disk I purchased for activation/registration?

Yes, the retail disks are all the same and contain all versions once unlocked.

It is the Product Key which determines which version will activate - Premium, Ultimate, Pro, OEM, Upgrade, full, etc.

Well, upon returning to the location of install I'm confronted with the message that says my media is corrupt. I cannot find my retail CD. Is there anyway i can download the iso from somewhere and install it without a further purchase and use the coa provided with the disc i purchased?