MySQL missing .myi file--what does that mean?

I’ve got a database I’ve been using with the YaBBSE discussion forum package for quite a while, but last Friday, right around when the announcement about the MySQL 4 upgrade for my server went out, several of the tables in the database suddenly died.

Specifically, they seem to be missing the .myi index file, or at least so claims all the error messages PHPMyAdmin coughs up. Has anybody ever seen an error like this before? More importantly, does anybody know if this is something that a user can cause due to a script incompatiblity, or is this strictly a server issue?

I’m desperate to know, because I don’t want to try and piece the database back together (I already tried to repair it) until I figure out whether it’s a problem on my end, or some corruption (worse yet, some corruption that may get worse and spread to other tables if I keep using that database).

For reference, I’ve also had a support ticket in for two days and counting now, but there’s been no response so far. I understand that support must be overwhelmed with the MySQL upgrades and whatever maintenance shut down the panel, but I’m feeling a bit like I’ve slipped through the cracks here and at this point I’m just trying to find out if I can safely patch things up and restore my forums, or if I need to wait for DH to fix something.

I don’t know if this is related (my guess is that it is), but some of my users are now reporting webmail problems, more specifically errors like this:

Warning: User alias has already more than ‘max_user_connections’ active connections in /usr/local/ndn/web/squirrelmail-1.4.1/plugins/dreamhost_virtualhosts/setup.php on line 87

Warning: MySQL Connection Failed: User alias has already more than ‘max_user_connections’ active connections in /usr/local/ndn/web/squirrelmail-1.4.1/plugins/dreamhost_virtualhosts/setup.php on line 87
1049: Unknown database ‘dreamhost’

I have also a ticket submitted and have not heard anything.