Is this a new install or an upgrade? The error indicates that the primary key on the profiles table has not correctly been set to an identity column. This type of thing typically happens when a 3rd party module has altered database schema (e.g. added a trigger to a table) that conflicts with our upgrade scripts.  You can check this yourself by logging in as the host user, and going to host->host settings, and scrolling to the bottom where you can view the upgrade log (alternatively if you have file/ftp access look in the \Providers\DataProviders\SqlDataProvider folder for the *.log files).

Cathal