[TIMOB-10107] iOS: Build error while accessing the multi lingual filename

Titanium.UI.setBackgroundColor('#000');
    //creating the window
    var win1 = Titanium.UI.createWindow({
        title:'win 1',
        backgroundColor:'#fff'
        });
     //add window - navigation bar
     var modalWin = Ti.UI.createWindow();
     //nav bar
     var navmodal = Ti.UI.iPhone.createNavigationGroup({
        window:modalWin
        });
     win1.add(navmodal);
     //button for the nav bar
     var b2t = Titanium.UI.createButton({
       title:'Launch'
       });
     modalWin.RightNavButton = b2t;
     //button for the window
     var b1t = Titanium.UI.createButton({
       title:'Launch',
       height:40,
       width:200,
       top:270
       });
     win1.add(b1t);
     //Setting up the documentviewer
     var filename = Titanium.Filesystem.getFile('網上廣東話輸入法.pdf');
     z = Ti.UI.iPad.createDocumentViewer({url:filename.nativePath});
     //documentviewer with animation set on and a quicklook view poping up next to a view
     b1t.addEventListener('click', function(){z.show({animated:false,view:b2t});});
     //documentviewer with animation set off
     b2t.addEventListener('click', function(){z.show();});
     win1.open();