A better way to install OfficeScan is to edit the \\officescanserver\ofcscan\Autopcc.cfg\Autopcc.ini and change the [Install] section to this:
Uninstall=0
SilentInstall=1
SilentUninstall=1
NoPrescan=0
To run the install just SHELL "\\officescanserver\ofcscan\autopccp.exe" and that should be it.
Best of luck.
