I have three 1TB external USB hard drives attached to my Mac Mini. Today when I try to mount one of the drive partition with TrueCrypt, it gave me an error message saying "hdiutil attach failed no mountable file systems"

I know my password is correct because it will says "Incorrect password or not a TrueCrypt volume" if try any random password

I am trying to figure what caused this error what how to go about troubleshoot this. This is the only copy I have so I don't want to lose it.

I always format my external drives as two partitions. 1st partition as bootable Mac OS X Extended (Journaled) and 2nd partition as TrueCrypt Volume formatted as Mac OS X.

All three drives has been attached to my Mac Mini and turned on and working for couple days.

Recent events that happened that I am trying figure out what may have caused this could be:
1. Recent Mac OS X Software Update from Version 10.7.1 to 10.7.2
2. Tuxera NTFS trial version expired
3. The drive was originally formatted as 3 partitions of Mac OS X Extended, NTFS, Mac OS X Extended. I later reformatted it two partitions of Mac OS X Extended and TrueCrypt Mac OS X. I used GUID Partition Table this time instead of Master Boot Record to try it out.

The partition that I am having problem mounting is /dev/rdisk1s3 and /dev/rdisk1s2. rdisk1s3 is my TrueCrypt volume. rdisk1s2 is my Mac OS X volume. All other TrueCrypt volume on other drives works fine.

Can anyone suggest how I should go about fixing this?
Is it caused by Tuxera expired? But I don't really use NTFS.
Should I remove or upgrade it to full version to see it will fix it?

I am thinking of cloning the whole drive to another drive sector by sector so I can trouble this on the copied one to increase my chance of recover this. This is the only copy I have. What software can copy sector by sector on Mac?

Help!!! Really appreciate any one that can point me in the right direction!
Thank you!

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TrueCrypt Shows
Device
/dev/rdisk0: 298GB
/dev/rdisk0s1 200 MB
/dev/rdisk0s2 148 GB /
/dev/rdisk0s3 619 MB
/dev/rdisk0s4 148 GB / Volumes/BOOTCAMP

Disk 1 - GUID Partition Table
/dev/rdisk1s1: 931 GB
/dev/rdisk1s1: 200 MB
/dev/rdisk1s2 46.6 GB - Mac OS X - Cannot mount
/dev/rdisk1s3 884 GB - TrueCrypt Volume - Cannot mount

Disk 2 - Master Boot Record
/dev/rdisk2: 931GB
/dev/rdisk2s1 46.7 GB - Mac OS X
/dev/rdisk2s2 884 GB - TrueCrypt Volume

Disk 3 - Master Boot Record
/dev/rdisk3: 931 GB
/dev/rdisk3s1 46.7 GB - Mac OS X
/dev/rdisk3s2 884 GB - TrueCrypt Volume

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I am running
Mac OS X version 10.7.2
TrueCrypt 7.1
MacFUSE (Tuxera)
Tuxera NTFS (Trial)

I was able to retrieve the data using R-Studio for Mac and copied to another hard drive. I had to tell TrueCrypt not to mount but just open the volume. Highly recommend R-Studio if you run into same situation. The Disk Utility Verify and Repair disk was grayed out. I also removed the trial version of Tuxera NTFS before I started the recovery just in case.