can you please state the version of ePO and the agent(s) in question? (depending on ePO and agent versions this error could be fixed on the go).
To answer your question: it is not recommended to disable sequence error checking since this is a feature that helps you keep clients distinct even they are looking the same single client to the ePO server. If two (or more) clients report to the same ePO node because of the problem the article describes this means you miss actual status information as to which client needs attention and which is not, all you see is that a client is okay one time and may have problems (i.e. infections) at another time, you may take actions which affects the good client and not the bad one, not to mention the client physical information that keeps changing depending on which client reports properties to the single ePO node.
Thanks Attila, my problems also posted here https://community.mcafee.com/thread/55779 version 4.6 both epo and agent. All client not use dns local so now client just connect to epo by ip address. All old agent before May 2 2013 that can not connect to epo (see server.log) but new agent after May 2 that connect fine. If i reinstall agent on old agent that also connect again. I don't know how to make all old agent connect again because workgroup enviroment so i can not redeploy agent through Active Directory. So i intend disable sequence error checking on the ePO server
I asked version information because starting from a certain ePO and agent version (see: http://kc.mcafee.com/corporate/index?page=content&id=KB67473&actp=search&viewloc ale=en_US&searchid=1367913846404 ) the wrong sequence number of the agent can be regenerated.
With you ePO and agent versions please enable the "Duplicate Agent GUID" server task in ePO (see also http://kc.mcafee.com/corporate/index?page=content&id=KB65991 ). This causes the agent GUID whose sequence number does not match the one ePO registered with that GUID to be put in a blacklist. Once the agent detects the rejection message as a result of being on such a blacklist, it regenerates the GUID on the client. This results in a new node being created next time the agent attemtp to connect again.