SetWindowIcon on several different platforms

Hi everyone,

I'm having trouble setting the WindowIcon on different platforms. I'm using the a qrc file with the rcc tool and compiling that into my application. I'm using a PNG image data, 48 x 48, 8-bit/color RGB, non-interlaced for the icon.

It works great on Windows, it gives me a clean icon on the top menu bar and in the taskbar. But I can't get it to work on Linux (currently Fedora 12) without a warning. When I start the same application on F12 I get this:
Error: BadDrawable (invalid Pixmap or Window parameter) 9
Major opcode: 62 (X_CopyArea)
Resource id: 0x0
Even with the warning, the icon is changed in the bottom taskbar, it's the annoying warning I can't get rid of.

When I try this on OSX I get "QPixmap::scaled: Pixmap is a null pixmap" as a warning.

If I use a GIF image then no error..and no icon, same for a Windows ICO image.

I'm using Qt 4.8.5
Any ideas?