wrong links takes you to mysql error message

An observation: I typed in wrong link to site.com/test/testrc2 when it should have been site.com/testrc2

Error message:

Warning: mysql_error(): supplied argument is not a valid MySQL-Link resource in /home/site/public_html/test/inc/db.inc.php on line 228

I tried doing that and it always takes me to the "profile cannot be displayed" error page.  I'm on RC3.  doesn't help you but just letting you know that it may not be a common issue.