From: DeskNow Knowledge Base
http://www.desknow.com/kb/

How do I configure DeskNow to use ClamWin antivirus?
http://www.desknow.com/kb/idx/13/071/article/

ClamWin is a free antivirus for Windows. It is a port of the open source Clamav antivirus for Linux/Unix.

It is available for download at http://www.clamwin.net

The command line to invoke this antivirus should be:

C:\Program Files\ClamWin\bin\clamscan --database=C:\clamwin\clamwindb %FILE%

Note that you may have to adjust

  1. the location of clamscan.exe, if you did not install ClamWin in C:\Program Files\ClamWin
  2. the location of the antivirus database. The value can be found by right-clicking on the clamwin icon in the task bar, selecting 'Configure ClamWin' and going to the 'File Locations' tab. Important:  make sure that the path does not contain spaces. If it does, set it to a folder without spaces, like C:\clamwin\clamwindb as in the example.

Important: if you get the following error when testing the antivirus with DeskNow: " The antivirus returned an unexpected success result
code: 50 " , it means that ClamWin is not able to access the virus database. This will happen if you installed ClamWin only for an user account, and DeskNow is running as windows service, which uses by default the SYSTEM windows account. If you get this message you can use one of the following two solutions:

1. you can change the user account that the DeskNow service uses to run. This can be changed in the Services control panel, as the service properties. You can change it to your account. Note that when you upgrade DeskNow, you will have to re-set this setting

2. you can move the clamwin database to a folder that is accessible by every account. This can be done from within ClamWin's interface.

Also reinstalling ClamWin so that it is setup for all the users may help...