On Tisiphone, Frescobaldi had a segmentation fault immediately at startup after a KDE 4.3 update; the next update corrected that, luckily (OK, score wizard is still broken, there seem to be major overhauls somewhere). Now the problem has diffused to Archimedes' 10.3 / KDE 4.2 setup, and here it's rather sticky.
Frescobaldi is written in Python, so I tried running frescobaldi.py line-by-line from the build directory. Turns out that the PyKDE4.kdecore module is broken, it kills python as soon as you try importing anything from it. You can't use a different version, because it has to be in sync with your KDE build. I tried building the source RPM, however, it crashed building libakonadipart1.cpp :-(
Hell, I don't even use akonadi on 10.3 because it breaks down anyway...
Update: As of today, (July 6th), the python bindings from the KDE:42 repository seem to work, as well as frescobaldi. Frescobaldi 0.7.13 in combination with KDE 4.3 even displays the score wizard.