Thanks for trying to help. For info, the last entries in the log are now:
2011/07/08 15:32:22 Customization trying to save data
2011/07/08 15:32:22 BEGIN Writing store information
2011/07/08 15:32:22 Using existing store for this library
2011/07/08 15:32:22 END Writing store information
2011/07/08 15:32:22 Customization saved data
Segmentation fault
and the Mac OS X stack trace is:
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000008
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Thread 0 Crashed: Dispatch queue: com.apple.main-thread
0 QtGui 0x000000010399ff24 QAction::isVisible() const + 4
1 QtGui 0x000000010398b1d4 QMenuBar::macMenu() + 2116
2 QtGui 0x0000000103959bdb QMacInputContext::reset() + 47195
3 QtGui 0x0000000103959b20 QMacInputContext::reset() + 47008
4 QtGui 0x0000000103959b53 QMacInputContext::reset() + 47059
5 com.apple.AppKit 0x00007fff870146de -[NSApplication run] + 474
6 QtGui 0x0000000103963884 QDesktopWidget::resizeEvent(QResizeEvent*) + 12820
7 QtCore 0x00000001025a5144 QEventLoop:
rocessEvents(QFlags<QEventLoop::Proce ssEventsFlag>) + 68
8 QtCore 0x00000001025a5464 QEventLoop::exec(QFlags<QEventLoop::ProcessEventsF lag>) + 180
9 QtCore 0x00000001025a711a QCoreApplication::exec() + 186
10 QtGui.so 0x000000010353c69c sipQApplication::disconnectNotify(char const*) + 11228
11 org.python.python 0x00000001000d752d PyEval_EvalFrameEx + 25325
12 org.python.python 0x00000001000d95d6 PyEval_EvalCodeEx + 2118
13 org.python.python 0x00000001000d6f26 PyEval_EvalFrameEx + 23782
14 org.python.python 0x00000001000d95d6 PyEval_EvalCodeEx + 2118
15 org.python.python 0x00000001000d6f26 PyEval_EvalFrameEx + 23782
16 org.python.python 0x00000001000d95d6 PyEval_EvalCodeEx + 2118
17 org.python.python 0x00000001000d6f26 PyEval_EvalFrameEx + 23782
18 org.python.python 0x00000001000d8933 PyEval_EvalFrameEx + 30451
19 org.python.python 0x00000001000d95d6 PyEval_EvalCodeEx + 2118
20 org.python.python 0x000000010004f420 function_call + 176
21 org.python.python 0x000000010001e262 PyObject_Call + 98
22 org.python.python 0x00000001000cff87 PyEval_CallObjectWithKeywords + 87
23 calibre-launcher.dylib 0x0000000100012978 run + 677
24 calibre-debug 0x0000000100001dc0 main + 90
25 calibre-debug 0x0000000100001d44 start + 52