If you get this error : "amarokapp: symbol lookup error: amarokapp: undefined symbol: _ZN11KSystemTray9setPixmapERK7QPixmap", then check that amarokapp uses the correct libqt (check with : ldd `which amarokapp` | grep qt).
To fix it, you might have to remove any conflicting libqt and/or edit /etc/ld.so.conf so it pick up the correct version first.

[root@localhost main]# ldd `which amarokapp` | grep qt libqt-mt.so.3 => /usr/lib/qt3/lib/libqt-mt.so.3 (0x0e82d000)

[mike@localhost mike]$ amarok
amaroK: [Loader] Starting amarokapp..
amaroK: [Loader] Don\'t run gdb, valgrind, etc. against this binary! Use amarokapp.
amarok: BEGIN: App::App()
amarok: BEGIN: void App::fixHyperThreading()
amarok: Fix not enabled
amarok: END__: void App::fixHyperThreading() - Took 0.018s
amarok: BEGIN: EngineBase* EngineController::loadEngine(const QString&)
amarok: [PluginManager] Plugin trader constraint: [X-KDE-amaroK-framework-version] == 15 and [X-KDE-amaroK-plugintype] == \'engine\' and [X-KDE-amaroK-name] != \'void-engine\' and [X-KDE-amaroK-rank] > 0
amarok: [PluginManager] Plugin trader constraint: [X-KDE-amaroK-framework-version] == 15 and [X-KDE-amaroK-plugintype] == \'engine\' and [X-KDE-amaroK-name] == \'void-engine\' and [X-KDE-amaroK-rank] > 0
amarok: [PluginManager] Trying to load: libamarok_void-engine_plugin
amarok:
amarok: PluginManager Service Info:
amarok: ---------------------------
amarok: name :
amarok: library : libamarok_void-engine_plugin
amarok: desktopEntryPath : amarok_void-engine_plugin.desktop
amarok: X-KDE-amaroK-plugintype : engine
amarok: X-KDE-amaroK-name : void-engine
amarok: X-KDE-amaroK-authors : (Max Howell,Mark Kretschmann)
amarok: X-KDE-amaroK-rank : 1
amarok: X-KDE-amaroK-version : 1
amarok: X-KDE-amaroK-framework-version: 15
amarok:
amarok: END__: EngineBase* EngineController::loadEngine(const QString&) - Took 0.13s
amarokapp: symbol lookup error: amarokapp: undefined symbol: _ZN11KSystemTray9setPixmapERK7QPixmap

Making all in .
make[4]: Entering directory `/usr/local/src/amarok-1.4-beta2/amarok/src\'
/bin/sh ../../libtool --silent --tag=CXX --mode=link g++ -Wno-long-long -Wundef -ansi -D_XOPEN_SOURCE=500 -D_BSD_SOURCE -Wcast-align -Wconversion -Wchar-subscripts -Wall -W -Wpointer-arith -O2 -Wformat-security -Wmissing-format-attribute -Wno-non-virtual-dtor -fno-exceptions -fno-check-new -fno-common -DQT_CLEAN_NAMESPACE -DQT_NO_ASCII_CAST -DQT_NO_STL -DQT_NO_COMPAT -DQT_NO_TRANSLATION -o amarokapp -L/usr/lib -L/usr/lib/qt3/lib -L/usr/X11R6/lib -R /usr/lib -R /usr/lib -R /usr/lib/qt3/lib -R /usr/X11R6/lib main.o ../../amarok/src/amarokcore/libamarokcore.la libamarok.la ../../amarok/src/analyzers/libanalyzers.la ../../amarok/src/engine/libengine.la ../../amarok/src/plugin/libplugin.la ../../amarok/src/statusbar/libstatusbar.la ../../amarok/src/metadata/libmetadata.la -lkutils -lkio -lkdeui -lkdecore -lkhtml -lknewstuff -L/usr/lib -ltag -lGL ../../amarok/src/sqlite/libsqlite.la -ltunepimp
./.libs/libamarok.so: undefined reference to `KNS::ProviderLoader::ProviderLoader(QWidget*)\'
./.libs/libamarok.so: undefined reference to `KNS::Engine::Engine(KNewStuff*, QString const&, QWidget*)\'
./.libs/libamarok.so: undefined reference to `KNS::ProviderLoader::load(QString const&, QString const&)\'
collect2: ld returned 1 exit status
make[4]: *** [amarokapp] Erreur 1
make[4]: Leaving directory `/usr/local/src/amarok-1.4-beta2/amarok/src\'
make[3]: *** [all-recursive] Erreur 1
make[3]: Leaving directory `/usr/local/src/amarok-1.4-beta2/amarok/src\'
make[2]: *** [all-recursive] Erreur 1
make[2]: Leaving directory `/usr/local/src/amarok-1.4-beta2/amarok\'
make[1]: *** [all-recursive] Erreur 1
make[1]: Leaving directory `/usr/local/src/amarok-1.4-beta2\'
make: *** [all] Erreur 2