Difficulty loading ctt file

I was sent a ctt file that is supposed to contain messenger contacts.
Unfortunately, I can not seem to import the contacts.

From windows messenger:

File->Import Contacts from a Saved File

Then I chose the file, but I get an error message stating:

"This is not a properly formatted conatact list . . . "

Is this a matter of different messenger versions? Is there anything I
can do?