is your remoting container working? so only one specific user get error? this might be due to some data corruption. if you can provide some screenshot and detailed steps, it may help. which HF has you implemented in your 6.2.2 environment?
It Worked .
But could you please tell me ,why it was repeatedly impacting to only few user's.
i think those users probably has used this customized search before, and if those search criteria is customized by your IT, then after upgrade, if you didn't check those customization, you may encounter such issue.