Very important! Missing .dll files

Hi There!
I scan my whole computer regularly. Yesterday after finishing scan process.
A message will came. It says: Very important! .dll file missed. So please recover the .dll file immediately or you can lost your some saved data.
Remove Shared Component
The system indicates that the following shared file is no longer used by any programs and may be deleted.
D:\WINNTsystem32ZoneLabsvsruledb.dll
If any programs are still using this file and it is removed those programs may not function. leaving this file will not harm your system. If you are not sure what to do you should select the No to All button. Do you want to remove the shared file?
But windows run perfectly every times. Which .dll file is missed? Why it is missing? How can I recover it? Please tell me with best answer.
