Multi-site Install Problem

I did a clean install of Drupal 6-rc4 on AN Hosting and created files for three domains (which I've had running before).

I went to www.domain1.com/install.php and went thru the dialog. The install procedure created all the database tables, emailed the notice that the admin account was created, but when I tried to go to the site, I got: "PHP MySQLi support not enabled." I checked the settings.php and found that it didn't exist (just the default-settings.php).

I went to www.domain2.com/install.php and went thru the dialog. Everything worked fine!

I went to www.domain3.com/install.php and went thru the dialog. Same problem as with domain1!

I copied the settings.php file from domain2 to the other two domains (in sites/domain1.com and sites/domain2.com), changed the database url to point to the appropriate databases (and ensured that it was mysql: and not mysqli:), but still get the same behavior.

I had this stuff working with a previous drupal release and the same directory/domain setup with no problems.

Any ideas?

PS - AN Hosting uses CPanel and sets up two of the domains as "parked". Interestingly, the problem is with the primary domain and one of the "parked" domains.