Was there any more specific information that was included in the report that was generated? I know that throughout the site in the code there is use of the 'or die(mysql_error())'. This code will print out a mysql error if an error occurs with the query. In this error it is mentioned that the query is a MySQL query.
Since it was not determined how the vulnerability was found I'm not sure if this is what is being referred to but it sounds like it would match. If this is the case you could test it out by making a backup of your site first, then do a site wide find and replace for:
and remove the mysql_error() so that it is like this:
If you can run this check on the updated version of the powerstore and do not get this issue then it would indicate that this is the problem. The bad thing about removing this is that you will not get an error if one occurs within the sql on the site.