Cannot start Hyperic Agent in CentOS

Dear all,

I'm installing the Hyperic Agent 5.8.4.2 into a CentOS 6.6 box. When I try to start the agent by  hq-agent.sh start command, it gave me the following error:

[root@fbdlvmtool12 bin]# ./hq-agent.sh start

Starting HQ Agent...... running (3462).

Error: /tmp/agent.encrypt.lock is locked. can't continue.

org.hyperic.hq.agent.AgentConfigException: /tmp/agent.encrypt.lock is locked. can't continue.

        at org.hyperic.hq.agent.AgentConfig.ensurePropertiesEncryption(AgentConfig.java:273)

        at org.hyperic.hq.bizapp.agent.client.AgentClient.ensurePropertiesEncryption(AgentClient.java:1437)

        at org.hyperic.hq.bizapp.agent.client.AgentClient.initializeAgent(AgentClient.java:1207)

        at org.hyperic.hq.bizapp.agent.client.AgentClient.main(AgentClient.java:1372)

However I cannot see there is any file in the address  /tmp/agent.encrypt.lock

Any suggestions how what maybe the cause and how to troubleshoot this error?

Thanks

Silvester