This indicates an attack attempt against a Cross Site Scripting vulnerability in Apache OpenMeetings.
The vulnerability is due to insufficient sanitizing of user supplied inputs in the application while handling maliciously crafted requests. An attacker can exploit this by tricking an unsuspecting user into visiting a malicious webpage and execute arbitrary script code within the context of the users' browser.
Apache Software Foundation OpenMeetings 1.9.x to 3.0.7
System Compromise: Remote attackers can execute arbitrary script code within the context of the target user's browser
Apply the most recent upgrade or patch from the vendor