i have similar issue with the new pages i added to my smf. when i load my custom pages it will display database not selected, Note: i create a new table in my smf database called news. in my new page i called the SSI.PHP just because i included recent post function.
Don't hijack such an old topic, especially as it is already marked as solved, I'm splitting this for you.
And can we see the code you're running?