[felice2011]

You check ...

[Languages]
Name: eng; MessagesFile: compiler:Languages\English.isl

You insert "english.ini" inside the "Files" folder ...english.rar ..

Insert the same name to be compiled ...

Source: "Files\english.ini"; DestDir: "{tmp}"; Flags: "dontcopy";

Same thing for the temporary extraction ...

ExtractTemporaryFile('english.ini');

Add this switch here written in red:

if ISDoneInit(ExpandConstant('{src}\records.inf'), $F777, Comps1,Comps2,Comps3, MainForm.Handle, {#NeedMem}, @ProgressCallback) then begin
        repeat
        case ActiveLanguage of
        'eng': ChangeLanguage('English');
        end;
          if not SrepInit(ExpandConstant('{app}'),512,0) then break;
          if not PrecompInit(ExpandConstant('{app}'),128,PCFVer) then break;
          if not FileSearchInit(true) then break;
          if not ISArcExtract    (0, 100, ExpandConstant('{src}\data.arc'), ExpandConstant('{app}'), '', false, '', ExpandConstant('{tmp}\arc.ini'), ExpandConstant('{app}\'), notPCFonFLY{PCFonFLY}) then break;
          if not ShowChangeDiskWindow ('bla bla bla.', ExpandConstant('{src}'),'data.arc') then break;
          FindHandle1:=ISFindFiles(0,ExpandConstant('{app}\*.ogg'),ColFiles1);
          ExecError:=false;
          while not ExecError and ISPickFilename(FindHandle1,ExpandConstant('{app}\'),CurIndex1,true) do begin
            InFilePath:=ISGetName(0);
            OutFilePath:=ISGetName(1);
            OutFileName:=ISGetName(2);
            ExecError:=not ISExec(0, 0, 0, ExpandConstant('{tmp}\oggdec.exe'), '"'+InFilePath+'" -w "'+OutFilePath+'"',ExpandConstant('{tmp}'),OutFileName,false);
          end;
          ISFindFree(FindHandle1);
          if ExecError then break;
          ISDoneError:=false;
        until true;
        ISDoneStop;
      end;

I simulated the same mistake that initially gave you ...



As you can read the error is written in Italian, because I translated the error line within the "English.ini" files in Italian.
Same thing you can do if you do not have file (*.ini) preconfigured in your language.

EDIT:The only thing that does not come back, that during installation I have not any progressbar in the task bar, as the picture you posted, maybe because I use w7.