OS crashes on every use Yosemite

Everything started fine. I was learning how to use OpenSesame. But, then, it started to crash on every use. Now, I can't do anything. Overtime I try to interact with an item, OpenSesame crashes. I am using Mac OS 10.10 Yosemite.

Here's part of the error box.

Process:               OpenSesame [632]
Path:                  /Volumes/VOLUME/OpenSesame.app/Contents/MacOS/OpenSesame
Identifier:            nl.cogsci.osdoc
Version:               2.9.6 (2.9.6)
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           OpenSesame [632]
User ID:               501

Date/Time:             2015-06-03 15:28:07.886 +0200
OS Version:            Mac OS X 10.10.3 (14D136)
Report Version:        11
Anonymous UUID:        516182FE-FDB8-422F-8BA4-4232689BFEE2


Time Awake Since Boot: 1700 seconds

Crashed Thread:        0  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_BAD_ACCESS (SIGABRT)
Exception Codes:       KERN_INVALID_ADDRESS at 0x0000000000000018

VM Regions Near 0x18:
--> 
    __TEXT                 0000000100000000-000000010000a000 [   40K] r-x/rwx SM=COW  /Volumes/VOLUME/OpenSesame.app/Contents/MacOS/OpenSesame

Application Specific Information:
abort() called

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib          0x00007fff90884286 __pthread_kill + 10
1   libsystem_c.dylib               0x00007fff8de3ab53 abort + 129
2   org.python.python               0x00000001047f1a9a Py_FatalError + 49
3   libsystem_platform.dylib        0x00007fff90d61f1a _sigtramp + 26
4   ???                             0x00007fff3f800000 0 + 140734258741248
5   com.apple.AppKit                0x00007fff8a7bee59 -[NSWindow(NSDrag) dragImage:at:offset:event:pasteboard:source:slideBack:] + 135
6   QtGui                           0x0000000105b97963 0x105b6c000 + 178531
7   QtGui                           0x0000000105bf2d7b QDrag::start(QFlags<Qt::DropAction>) + 73
8   QtGui.so                        0x00000001054e63c6 0x105450000 + 615366
9   org.python.python               0x00000001047d6979 PyEval_EvalFrameEx + 14227
10  org.python.python               0x00000001047d96d1 0x10474f000 + 566993
11  org.python.python               0x00000001047d6553 PyEval_EvalFrameEx + 13165
12  org.python.python               0x00000001047d2fb4 PyEval_EvalCodeEx + 1387
13  org.python.python               0x0000000104777bf5 0x10474f000 + 166901
14  org.python.python               0x0000000104759ad7 PyObject_Call + 99
15  org.python.python               0x0000000104764962 0x10474f000 + 88418
16  org.python.python               0x0000000104759ad7 PyObject_Call + 99
17  org.python.python               0x00000001047d8e2e PyEval_CallObjectWithKeywords + 93
18  sip.so                          0x00000001053846cd sip_api_invoke_slot_ex + 439
19  QtCore.so                       0x0000000104f79966 PyQtProxy::invokeSlot(qpycore_slot const&, void**, int) + 162
20  QtCore.so                       0x0000000104f79832 PyQtProxy::unislot(void**) + 184
21  QtCore.so                       0x0000000104f79769 PyQtProxy::qt_metacall(QMetaObject::Call, int, void**) + 111
22  QtCore                          0x00000001051b6c8d QMetaObject::activate(QObject*, QMetaObject const*, int, void**) + 1809
23  QtCore.so                       0x0000000104f4c680 sipQTimer::timerEvent(QTimerEvent*) + 98
24  QtCore                          0x00000001051b2fe3 QObject::event(QEvent*) + 51
25  QtCore.so                       0x0000000104f4c614 sipQTimer::event(QEvent*) + 98
26  QtGui                           0x0000000105be6ed5 QApplicationPrivate::notify_helper(QObject*, QEvent*) + 195
27  QtGui                           0x0000000105be8419 QApplication::notify(QObject*, QEvent*) + 889
28  QtGui.so                        0x0000000105494a24 sipQApplication::notify(QObject*, QEvent*) + 122
29  QtCore                          0x00000001051a2bb8 QCoreApplication::notifyInternal(QObject*, QEvent*) + 118
30  QtGui                           0x0000000105bea1ba 0x105b6c000 + 516538
31  QtGui                           0x0000000105ba3f01 0x105b6c000 + 229121
32  com.apple.CoreFoundation        0x00007fff904ee2e4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 20
33  com.apple.CoreFoundation        0x00007fff904edf73 __CFRunLoopDoTimer + 1059
34  com.apple.CoreFoundation        0x00007fff9056153d __CFRunLoopDoTimers + 301
35  com.apple.CoreFoundation        0x00007fff904a9608 __CFRunLoopRun + 2024
36  com.apple.CoreFoundation        0x00007fff904a8bd8 CFRunLoopRunSpecific + 296
37  com.apple.HIToolbox             0x00007fff8969756f RunCurrentEventLoopInMode + 235
38  com.apple.HIToolbox             0x00007fff896972ea ReceiveNextEventCommon + 431
39  com.apple.HIToolbox             0x00007fff8969712b _BlockUntilNextEventMatchingListInModeWithFilter + 71
40  com.apple.AppKit                0x00007fff8a59a9bb _DPSNextEvent + 978
41  com.apple.AppKit                0x00007fff8a599f68 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 346
42  com.apple.AppKit                0x00007fff8a58fbf3 -[NSApplication run] + 594
43  QtGui                           0x0000000105ba4936 0x105b6c000 + 231734
44  QtCore                          0x00000001051a0215 QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 77
45  QtCore                          0x00000001051a0386 QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 356
46  QtCore                          0x00000001051a3009 QCoreApplication::exec() + 199
47  QtGui.so                        0x0000000105495be2 0x105450000 + 285666
48  org.python.python               0x00000001047d6979 PyEval_EvalFrameEx + 14227
49  org.python.python               0x00000001047d2fb4 PyEval_EvalCodeEx + 1387
50  org.python.python               0x00000001047d6ff9 PyEval_EvalFrameEx + 15891
51  org.python.python               0x00000001047d2fb4 PyEval_EvalCodeEx + 1387
52  org.python.python               0x00000001047d9640 0x10474f000 + 566848
53  org.python.python               0x00000001047d6553 PyEval_EvalFrameEx + 13165
54  org.python.python               0x00000001047d2fb4 PyEval_EvalCodeEx + 1387
55  org.python.python               0x00000001047d2a43 PyEval_EvalCode + 54
56  org.python.python               0x00000001047f2816 0x10474f000 + 669718
57  org.python.python               0x00000001047f28b9 PyRun_FileExFlags + 133
58  org.python.python               0x00000001047f23f9 PyRun_SimpleFileExFlags + 711
59  nl.cogsci.osdoc                 0x000000010000275b py2app_main + 2683
60  nl.cogsci.osdoc                 0x000000010000117a main + 650
61  nl.cogsci.osdoc                 0x0000000100000be4 start + 52