This icon file couldn't be found. If the path to the icon in the menu file is an absolute path, make sure that icon exists at that path in the package. If the path is relative or a simple filename, make sure the icon is installed in /usr/share/pixmaps, the default location.
If the icon is provided by another package on which this package depends, Lintian may not be able to determine that icon pages are available. In this case, after confirming that all icons are available after this package and its dependencies are installed, please add a Lintian override.