Here is a one off importer to fix the missing comments.
FTP into your server and rename the file dbtech/gallery/includes/class_import.php
to dbtech/gallery/includes/class_import_orig.php
Then upload the attached file to the folder dbtech/gallery/includes/
Run the import function as if you were importing your images again. It will not import any categories, albums or images, it will just update the comments.
After it runs, delete the file and rename dbtech/gallery/includes/class_import_orig.php
to dbtech/gallery/includes/class_import.php
Let me know how that works for you. I tested it out locally and it should work fine.
EDIT:
If you are not worried about importing after you get the comments updated you can just upload that file in place to the dbtech/gallery/includes folder and skip all the renaming stuff.
Just remember it's a tweaked file and if you need to import again for whatever reason you need to go back to the original from the package
very weird, check the comments table and see if they are actually there. The only thing I can think of is that the instance id didn't get set right maybe? If it is I'll give you a sql query to update it.