Error code 3012 basically means that Maximizer is unable to talk to the Pervasive database engine.
Typically, the resolution to the problem is to set the Pervasive engine to pre-load. Pre-loading forces the database to start when Windows starts. The easiest way to check for this is to hover your mouse over the Pervasive icon in the system tray. If it says, "pre-load", you're fine. If it says "auto-load" then that might be the cause of the problems. There is a document that covers this on Max's Top FAQ page.
If that doesn't work, the only other time I remember seeing this problem is when the person had a software firewall on their machine. Something like Black Ice, McAfee Firewall, or Norton Personal Firewall. The firewall was configured to block access to w3dbsmgr.exe (the Pervasive workgroup engine). Since Pervasive was not allowed to run correctly, Maximizer was never able to talk to it, hence the 3012 error.