This indicates an attack attempt to exploit an Insecure Deserialization Vulnerability in HP Intelligent Management Center.
A remote, unauthenticated attacker can exploit this vulnerability by sending a request message with a maliciously-crafted serialized object. Successful exploitation results in the execution of arbitrary code under the context of the SYSTEM or root user.
HP Intelligent Management Center 7.3 E0506P09 and prior
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.