Cannot add windows 2008 R2 host

Hi everybody.
I'm experiencing an issue while adding a Windows 2008 R2 host to the EventLog Analyzer by providing a domain or local admin credentials.
The error returned is "Access is denied". Same error is returned when trying to connect by wbemtest, with the same error code (0x80070005).
I've checked on help support pages, on manual and on forum and applied many tips. Below are the results of my tests.

No firewall is running on the remote host.
No network firewall limitations (TCP, UDP and ICMP packets can flow from ELA to remote host starting by and ending on any port).
DCOM is enabled on remote host and related Security permissions are exactly the same as another host in the same lan and domain and which is perfectly reachable and monitorable by ELA.
No effect also after using an ad-hoc-created local admin and giving him full permission on every COM security option and on root WMI control security properties.
Remote administration is enabled on remote host.
Management agent cannot be deployed from ELA console, and local installation fails with message "The installer was interrupted before ManageEngine EventLog Analyzer 8 - Agent could be installed. You need to restart the installer and try again". This happens both with domain admin account and with local admin one.
I've followed the procedures outlined here . Every check was fine (DCOM is enabled and user - domain and local admins - is valid on remote machine).