On symbian phones you can’t just use ico files to set the icon. you need to follow this procedure.
1) Create a svg file
you can do that using the free tool – inkscape.
2) now convert svg to tiny svg.
you can do that using nokia’s builtin svg convertor.
its found in C:S60devicesS60_5th_Edition_SDK_v1.0S60toolssvg2svgtinstaller
3) Install this.
4) convert into svgt
5) goto the .pro file of your project.
copy this symbian {
ICON = icon_1.svg
}
where icon_1.svg is your icon file.
you will see your icon show up.
its as simple as that.