Chapter 3 Authentication for FortiOS 5.0 : Agent-based FSSO : Troubleshooting FSSO : Can’t find the DCagent service : Solution
  
Solution
To verify that the DCagent is installed properly
1. Check that DCagent.dll exists in %windir%\system32 folder.
2. Check that the registry key exists: [HKEY_LOCAL_MACHINE\SOFTWARE\Fortinet\FSAE\dcagent]
If both exist, the DCagent is properly installed.