Apparently there are some third-party screen savers out there that use Macromedia's Flash Player to render the images when the screen saver kicks in.
A third-party screen saver is something that you installed yourself and should not be confused with the built in screen saver that is part of your computer's operating system.
These screen savers are coded to look for the file flash.ocx and recent version of Macromedia's Flash application now name the same file flash9.ocx or even flash9a.ocx.
The reason you get this error message is that the screen saver is looking for the old file name.
Personally, I don't really care for third-party screen savers. I find them to be problematic and sometimes even detrimental the efficiency of a computer. I just use the built in screen saver to protect my display.
To fix this problem, you have two options. The first one would be to simply uninstall the screen saver. Once that is done the error will go away.
The second option is for those of you who simply cannot bear to part with your screen saver and is a bit more involved.
What you will need to do is find the flash9.ocx file and copy it as flash.ocx.
To do this, browse to the C:\Windows\System32\Macromed\Flash folder. Locate the flash9.ocx file and right click it and select copy. Now just right click in a blank spot of the same folder and select paste. You will then find you have a file called Copy of Flash9.ocx in the folder. Right click the new file and select rename and change the name to flash.ocx.
Once complete, the error should be history.