If you see the following cryptic errors when trying to install FCS, then the chances are you need to install the .Net Framework 1.1 AND SP1.
[06/04/2010 10:47:11] Task (Install Collection Server Component) The following process failed. Process: C:\Windows\system32\msiexec.exe Exit code: 1603 Number of tasks completed: [06/04/2010 10:47:12]