Cubase 4 and Score error 7

Suddenly, when I am inputting in step mode, or editing the key list, the score window suddenly closes and I get the ‘Cubase needs to close, serious error blah blah, save your project, etc, etc.’ When I cancel the error message, I get a little palette that says, ‘score error 7’. This has never happened to me before, and it only happens on this one project. The project is not that large compared to other projects that work fine. I can’t figure out what is different. If I close the score window, then it is OK, but I need the score window to edit and input properly. I attach a log file of the last one that happened.
Can anyone tell me what is wrong with my particular project file that is causing this?

Typically this would be due to damaged App Data or Prefs. What operating system are you on? What version and build of Cubase 4 do you have installed?

WinXP SP3 & Cubase 4 build I have 4GB RAM and am using a separate hard drive for the big VST instruments (Vienna Instruments).
All my other projects do not have this problem even though some of them are MUCH larger. When the score window is up, it can crash the instant I input the first note in step mode from a keyboard.
I could attach the log file except you don’t allow text. If you want to see it, tell me how to send it.
I would appreciate knowing what to do but, in the meantime to get going, I am going to export the midi file, read it back in to a new project and see if it helps.

I agree with the idea to export the MIDI file and start a new project.

Here are instructions to clear your Application Data to give C4 a fresh start:

First, please shut down Cubase. Then go to the Start menu, All Programs, Cubase 4, Cubase 4 Application Data Folder. Press the Up Folder Button (green arrow pointing up in the top left corner). This will put you in the Steinberg app data folder. Trash any Cubase or Nuendo folder that you see here. This will trash your key commands, preferences, sound card settings, etc. It also should clear up the problem you are having. Restart Cubase. You will need to reset your audio outputs (Devices, Device Setup, VST Audio System).