Ignoblekey Error: Problem decoding key; unexpected DB format

If you get the following error after running ignoblekey.pyw
"Error: Problem decoding key; unexpected DB format?"
you can either find and delete your 'ClientAPI_v012.db' file then re-authorize BDReader with your account information,
or just use the key-derivation script (ignoblekeygen).

Both ignoblekey and ignoblekeygen will produce the same output when they work correctly.

[ch mn]

This is confusing... trying to find up to date instructions across several threads and multiple posts.

First question:
Do I need pycrypto to use ignoblekey or is that just for ignoblekeygen.py?

Second question:
With nook desktop reader 2.5.1.xxx, will ignoblekey work at all?
It is not clear from the seemingly conflicting posts on the threads.

I was getting the "Error: Could not locate B&N Reader installation"
I made the following modification to ignoblekey.pyw
BN_APPDATA_DIR = r'Barnes & Noble\BNDesktopReader'

and got the "Error: Problem locating B&N Reader DB". I made the following modification:
dbpath = glob.glob(os.path.join(bndir, 'ClientAPI*.db'))

and got the "B&N User Key not found. Unexpected DB format?"

I deleted ClientAPI.db from by Application settings, but all the Nook reader asks for is my B&N account email and password. Which does not seem to fix the error. Am I supposed to do something with my account setting on the B&N Website?

Update:
ignoblekeygen worked, so the question still stands has the current versions of the nook desktop reader broken ignoblekey even after updating the directory/file names?

[kinbalight]

Hi guys, I have installed the tool, Python, and also the ignoblekey.pyw

Have changed the reader path to BNDesktopReader, and removed the "_" from the ClientAPI.*

However, when I run the ignoblekey.pyw, it still gives me the "B&N user key not found; unexpected DB format?" error.

How do I correct this?

Am running Windows Vista...

@kinbalight

Have you tried to use the ignobleepub v01.6 plugin for Calibre?