it is good news that your Moodle has been saved but I worry that if you got this message then your database was never properly migrated to Unicode while you were at Moodle 1.6.
The most common cause of this that I know of is that Moodle was installed using Fantastico, which creates a non-unicode database, but masks this fact by adding the following setting to "config.php":
$CFG->unicodedb = true;
With this setting, Moodle will assume that the database is unicode, and will not warn you or try to help you when could do so.
So please check through you courses and verify that there is no corruption of the text displayed on the various Moodle pages. If you find no errors, you can probably continue without any further trouble. However, if you find some characters do not display correctly, it might be sensible to do the incremental upgrade and unicode migration that I described in earlier posts on this thread.
best of luck!
Gordon