Where does the Enterprise Console save the downloaded files by default?
Under c:\programdata\sophos\update manager\update manager\*.*
 Can I install Sophos Anti-Virus "Silent"?

You cannot specify parameters for the 'standealoneinstaller'. This is only possible for setup files which are provided by the Enterprise Console or the Control Center via CID. A description of the existing parameters can be found here: http://www.sophos.com/support/knowledgebase/article/12570.html.

 Can I move the filing location, in which the Sophos Update Manager stores its files, to another partition?

Instructions on this can be found here: http://www.sophos.de/support/knowledgebase/article/63184.html.

 I get the error message "Code 80040406 Supply of software subscription 'Recommended' failed. Access to update source denied or source otherwise unavailable." What does this mean?

From time to time this error is "normal" and usually occurs when the configured parent itself is simultaneously performing an update of its files. Also refer to http://www.sophos.com/de-de/support/knowledgebase/66176.aspx.

 Firewallconfiguration between the Sophos enterprise Console and the Sophos Client

Because the communication between the Enterprise Console and the Sophos client is RPC based and some more Ports are used for the communication it would be the easiest way to disable firewallblocking between the Sophos Enterprise Console and the Sophos Client