Probably what is happening is that you're point to a blank smtracedefault.txt file or in any case to a file where it was deleted or corrupted the content.
I suggest you to recreate one and point again the Management console to this file.
Just for instance, use this example:
components: AgentFunc/Init, AgentFunc/IsProtected, AgentFunc/Login, AgentFunc/ChangePassword, AgentFunc/Validate, AgentFunc/Logout, AgentFunc/Authorize, Server/Connection_Management, Server/Policy_Object, Server/Administration, Server/Audit_Logging, Server/Policy_Server_General, IsProtected, Login_Logout/Authentication, Login_Logout/Policy_Evaluation, IsAuthorized/Policy_Evaluation, Tunnel_Service, JavaAPI, ODBC, TXM/License, ProxyAgent, Fed_Client/Request_Info
data: Time, Message, AgentName, Resource, User, Pid, Tid, Date, Function, ReturnValue, Domain, Realm, Policy, Rule, Directory, AgentType, SearchKey, ErrorString, ErrorValue, Action, RealmOID, Query
version: 1.1
Cheers,
Pasquale