PeripheralErrorCode:10125 AgentID:1000 UniqueObjectID:agent.5000.1000
     MessageID:eControlFailureConf MessageType:eSetAgentStateRequest
     ErrorMessage:IPCC Error [10125]You have attempted to log into an invalid
     instrument.  If you think it is correct there could be a configuration error.
      Otherwise, check the number and try again. FilterTarget:agent.5000.1000

I recently ran into this error and for the life of me could not figure out what was wrong.  So, the first thing I did was make sure it was happening on more than one PC, check.  Next, checked if it was happening with more than one phone, check.  Next, check if it happens with both PGs… this is where I noticed that I could login to one PG, but not to the other.  Which then lead me to check the configuration of both PGs and found that the PG configuration for the PG where the login was failing had an agent extension of 7 digits instead of 10 digits.  Thus why CTIOS was rejecting my login to a phone with an extension with 10 digits.

Presto!

~david