To explain why the error occurs you first need to consider that there are two modes an execution server can operate in:
1) "Not utilized" This is a type of "standby" mode, where most of the Execution Server components are inactive and the server is not being accessed by the application.
2) "Utilized" The server is aware to be used by some specific application server (this info is stored in the "AgentBase" directory locally).
Under normal circumstances the mode "Not utilized" corresponds to “Inactive” when viewed in “SCTM | Administration | Locations | Selected Location | Status” and "Utilized" corresponds with "Active". The error mentioned occurs, if the Execution Server is "Active" in terms of the Application server and Database, but locally operates in the "Not utilized" mode (i.e. it is not aware of being used). This typically occurs in two cases.
1) The "Agent Base" directory or subdirectories have been manually deleted on the Execution Server.
2) There is a mismatch of the application server and execution server build. If this is the case then in the execution server log you would see the following error frequently logged, that the server is in mode "Not Utilized": I;OV;2010-01-11;11:30:40;BCA;main; Mode: Not Utilized I;DT;2010-01-11;11:30:40;BCA;main; Created application data directory C:\Documents and Settings\All Users\ Application Data \Borland\SCC35
This log entry means that the "AgentBase" directory did not exist at this start-up time and was subsequently created. Therefore the "Activate" action in SCTM administration must have occurred before this point.
In either case, to resolve this error please go to “SCTM | Administration | Locations | Selected Location” and deactivate the Execution Server before reactivating it again.