error while trying to digital sign winvnc.exe

[winman]

I am trying to digital sign winvnc.exe so that antivirus does not show it as virus or malware. But when i try to digital sign winvnc.exe i am getting error. I hav tried digital signing other exe's and it works. It's not problem with digital sign tool. Can i digital sign winvnc.exe? If possible then what changes i have to do(if any).Please reply me as soon as possible.

[RudiDeVos]

We also use signtool, no special options.
What's the error ?

[winman]

I got following error while digital signing winvnc.exe
C:\>signtool.exe sign /f \\pc2\g\SOFTWA~1\CODING~2\SARALD~1\DIGSIG~1\VERISI~1\W
INMAN~2.PFX /t http://timestamp.verisign.com/scripts/timstamp.dll /p ********
F:\vnc\NEWFOL~3\winvnc.exe
Done Adding Additional Store
SignTool Error: ISignedCode::Sign returned error: 0x80070057
The parameter is incorrect.
SignTool Error: An error occurred while attempting to sign: F:\vnc\NEWFOL~3\wi
nvnc.exe

But i can digital sign other application successfully.so i think it is not problem with sign tool.