Well, pulling the side panel off usually results in a 0-0-2 error, but I think that it's still reporting the same issue. Is the side panel still off when you turn the system on? If so, try putting the side panel back on, and booting it.
Check to see if you have "Third Party Service" enabled, or if the system has a PIC2 board in it, and is a 9.51 revision level.
If it has just a PIC board in it, you will need to have "Third Party Service" enabled. To do this, see if your system has a Functional Location sticker on it, it should be a silver sticker, with 400-XXXXXX etched onto it. If it does not, call up Siemens and see if you can give them the serial number of the system for the history on it. Let them know you own the system, or ask the tech support person you speak with if you can get the email address to create a functional location for the system. Once this is created, you can call Siemens again and request a Third Party Service Key. Once you have that, enter it into the Feature Control and it will allow you to boot the system properly again.
Universal Diagnostic Solutions