kdenlive crashes on most operations

I've not used kdenlive for a very long time. In the past I used both debian packages and kdenlive built from source (up to version 0.5). Now I'm trying to edit some videos using 0.7.5 debian packages + KDE 4.2.4, but it crashes with most common task, as save a project or load a clip in the time line.
If I try to save a project, this is what I get:
Terminal output:
carlos@debian-carlos:~$ kdenlive
KCrash: Application 'kdenlive' crashing...
sock_file=/home/carlos/.kde/socket-debian-carlos/kdeinit4__0
Backtrace:
Application: Kdenlive (kdenlive), signal SIGSEGV
[Current thread is 0 (LWP 4654)]

Thread 3 (Thread 0xb1f70b90 (LWP 4668)):
#0 0xb8087424 in __kernel_vsyscall ()
#1 0xb664c2e2 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/i686/cmov/libpthread.so.0
#2 0xb67520b4 in pthread_cond_timedwait () from /lib/i686/cmov/libc.so.6
#3 0xb8063b49 in mlt_consumer_get_frame () from /usr/lib/libmlt.so.1
#4 0xb664989e in pthread_mutex_lock () from /lib/i686/cmov/libpthread.so.0
#5 0xe8758bff in ?? ()
#6 0x0140868b in ?? ()
#7 0xc0850000 in ?? ()
#8 0xff63840f in ?? ()
#9 0x408bffff in ?? ()
#10 0xff55e904 in ?? ()
#11 0x768dffff in ?? ()
#12 0xe5895500 in ?? ()
#13 0x8938ec83 in ?? ()
#14 0x7d8bfc7d in ?? ()
#15 0xf45d8908 in ?? ()
#16 0xe8144d8b in ?? ()
#17 0xfffd4540 in ?? ()
#18 0x8df9c381 in ?? ()
#19 0x75890003 in ?? ()
#20 0x18758bf8 in ?? ()
#21 0x2274ff85 in ?? ()
#22 0x2d74c985 in ?? ()
#23 0x8508578b in ?? ()
#24 0x8b0375f6 in ?? ()
#25 0x458b0c77 in ?? ()
#26 0x39c8010c in ?? ()
#27 0x8b0b7fd0 in ?? ()
#28 0x048d1055 in ?? ()
#29 0x0c473b16 in ?? ()
#30 0x5d8b177e in ?? ()
#31 0xf8758bf4 in ?? ()
#32 0x89fc7d8b in ?? ()
#33 0x66c35dec in ?? ()
#34 0x08578b90 in ?? ()
#35 0xcfebd189 in ?? ()
#36 0x45b70f90 in ?? ()
#37 0x5589660c in ?? ()
#38 0x4d8966ee in ?? ()
#39 0x758966f0 in ?? ()
#40 0x458966f2 in ?? ()
#41 0xec458dec in ?? ()
#42 0x08244489 in Wizard::checkMltComponents (this=) at /usr/include/qt4/QtCore/qstring.h:413

Thread 2 (Thread 0xb176fb90 (LWP 4669)):
#0 0xb8087424 in __kernel_vsyscall ()
#1 0xb664bfb5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/i686/cmov/libpthread.so.0
#2 0xb675205d in pthread_cond_wait () from /lib/i686/cmov/libc.so.6
#3 0xb27ffc7c in ?? () from /usr/lib/mlt/libmltsdl.so
#4 0x0920ee2c in ?? ()
#5 0x0920ee5c in ?? ()
#6 0x00000099 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)

Thread 1 (Thread 0xb5cc3710 (LWP 4654)):
#0 0xb8087424 in __kernel_vsyscall ()
#1 0xb66ff376 in nanosleep () from /lib/i686/cmov/libc.so.6
#2 0xb66ff18e in sleep () from /lib/i686/cmov/libc.so.6
#3 0xb7e870f8 in ?? () from /usr/lib/libkdeui.so.5
#4 0x00000000 in ?? ()

I hope you can help me come back to kdenlive.
Regards
Carlos