Mutual information list is incompatible
A mutual information list derives from an index file, and knows which index file it derives from when computed. Normally when it opens up, it opens up the corresponding index file too. If that index file is not found on your PC or has been renamed, you will see this message. The mutual information can still be accessed but a) what you see in terms of Frequency and Alphabetical lists refers to a different index file, and b) it will not be possible to get concordances directly from the listing.