I had to reformat my computer so I backed up all my files, including encrypted chat logs, to another computer.  Now that this computer is up and running again I can't seem to open my old chat logs.  I've downloaded msn and Messenger Plus again and it just created new chat logs for me.  When I go to click on my old, still encrypted, ones it says "This file hasn't been encrypted by Messenger Plus! (or the file is corrupted)."

How can I open my old chat logs?

EDIT:

I have over 200 individual logs that can't be opened.  (over 10MB worth).  I could probably narrow that down to about a fourth or a third of things that are important.  I just really hope I don't lose these, it is afterall nearly a year and a half of logs.
It is possible that I could send a couple of these logs with the password that went with them if anyone thinks they can open them.  It's about time for me to get a new password for all my stuff anyways.

Can anybody help me out?

Please send me one of your logs along with your password, I'll check it out: mplus@patchou.com .

Patchou

ok I just sent an email with a chat log attatchment and my original password.  Thanks for taking time to do this.
Bongopukerat@gmail.com

He'll reply when he has information.

So it's been over a month now...Is it safe to assume that nothing can be done?

Although the error you get doesn't exactly indicate the following cause, you might try it out:

Make sure you've updated your computer fully (including SP2 if you have XP)...

Go to the Windows update site (with MSIE!) and install every update. After that reboot and check again the Windows update site if there are any new updates which are only visible after you've installed other updates. Repeat this process untill nothing is shown on the update site anymore.

After all that reboot and try again to access your logs. Also make absolutely sure you have the correct password for each individual encrypted log file.