Did you install bootmii or preloader?
You probably wont get any problems with apps, most bricks are caused with messing about with WAD files. Get hold of hombrew browser (google it) let it update. It like wii's own app browser with lots of cool stuff that download straight to sd card through the wii.
Here is link for homebrew browser: http://wiibrew.org/wiki/Homebrew_apps/Homebrew_Browser