OK, I ran SA from the prompt and when attempting to preview, it complains with:
Cannot mix incompatible Qt library (version 0x40802) with this library (version 0x40800)
dumps core and abends the preview thread.
I'm on Fedora 16 with a current update of KDE (4.8.4).
Now somebody appears to be too sensitive with the versions here. Or some update did not go through properly.
Googling dug up this reply on the kde forum
It is probable your application has a RPATH set in it, meaning it internally has paths stored toward the recommended libraries to use. Have you tried rebuilding your application after changing LD_LIBRARY_PATH?
Of course I did not compile but Sencha did so maybe this will help someone.