-Uninstall the Altiris Agent using the Command Prompt'
"C:\Program Files\Altiris\Altiris Agent\AeXAgentUtil.exe" /clean
-Change the Registry Value
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\CommonFilesDir
E:\Program Files\Common Files (to) C:\Program files\Common files
-Once again Reinstall the Agent.