The following errors are properly speaking errors pertaining to the script host, but you may see them occasionally.
An error has been recorded to be passed between script engine and host. The host needs to pass the error code to the caller.
Script engine has reported an unhandled exception to the host via IActiveScriptSite::OnScriptError. Host can ignore this error.
A script error is being propagated to the caller which might be in a different thread. The host should pass the error code to the caller.