Ordenar datos en un DBGrid con click en cabecera

[jhcaboverde]

Miren, el error que me da alguien sabe que es.

[DCC Error] Unit3.pas(166): E2251 Ambiguous overloaded call to 'Pos'
System.pas(16672): Related method: function Pos(const WideString; const WideString): Integer;
System.pas(18130): Related method: function Pos(const string; const string): Integer;
[DCC Warning] Unit3.pas(166): W1058 Implicit string cast with potential data loss from 'string' to 'RawByteString'
[DCC Error] Unit3.pas(167): E2251 Ambiguous overloaded call to 'Pos'
System.pas(16672): Related method: function Pos(const WideString; const WideString): Integer;
System.pas(18130): Related method: function Pos(const string; const string): Integer;
[DCC Warning] Unit3.pas(167): W1058 Implicit string cast with potential data loss from 'WideString' to 'RawByteString'
[DCC Fatal Error] Unit1.pas(36): F2063 Could not compile used unit 'Unit3.pas'