Cant set icon's picture to a file that is located in the file system , and not in the qrc

Im using qt4 to compile a tray icon application for Ubuntu 12.10..
As I run the tray icon on a Ubuntu machine I get the following error:

   Could not save icon as '/tmp/sni-qt_server_22456-
    MTXUll/icons/hicolor/16x16/apps/appName_22456_1fd07571a5278bdba6564f8b47480a18.png'
    ....

This error is thrown when trying to set an icon with a picture on the file system that is not a part of qrc package:

    trayicon->(QIcon("/usr/local/appName.appPic.png");

This code works for most of the linux distributions (earlier ubuntu, centos, etc.), but fails on Ubuntu with sni-qt

It can be fixed by using a picture that is included in the qrc, but this is not what im looking for, since the menu picture may be changed after compilation on my application.