issues with WMI in windows server 2003

Hello to everyone, I've problems when monitoring windows server 2003, always the collector tells me that it can not connect to port 135, but doing the tests locally the WMI service with some tools like WBEMTEST or PORTQRY seems working properly.

please help me to verify if this problem is in general with the version windows server 2003 or I must do something else.

thanks