on my system, a "ls -la /usr/lib/libmlt*" gives:

-rw-r--r-- 1 root root 154120 Sep 2 14:41 /usr/lib/libmlt.so.0.8.3
-rw-r--r-- 1 root root 118816 Sep 2 14:41 /usr/lib/libmlt++.so.0.8.3
lrwxrwxrwx 1 root root 17 Sep 2 14:41 /usr/lib/libmlt++.so.3 -> libmlt++.so.0.8.3
lrwxrwxrwx 1 root root 15 Sep 2 14:41 /usr/lib/libmlt.so.5 -> libmlt.so.0.8.3

my libx264 is in "/usr/lib/x86_64-linux-gnu/libx264.so.120" -- could there be a problem with the 64bit architecture?

The Wiz(z)ard says that everything is okay and lists all those codecs, including H.264. So this does not really help to track down any problems, I suppose.

Yes it does help, we know mlt is fine, Wizard says they are all there and I'm using Ubuntu 64bit and it all is working fine.

Nearer the top of this thread you say there is trouble with libmp3lame.

Look at this below .. Post #14 THEN look at the last post:-

http://www.kdenlive.org/forum/pcms16le-codec-not-found-even-though-it-there-fixed

normcross: thanks for your suggestion, it finally solved my problem. I had to manually add libmp3lame as well as libx264 to kdenliverc as described in the thread you linked to above. A first quick rendering test with a 5min video seems to be okay.

DiveO : Don't hijack this thread. Start a new thread for your problem

???

For me since I up-dated to MLT 8.2, Kdenlive started crashing like a m*****f*****!

It did this before but was fixed in 9.+, (currently on 9.2 which worked fine till now) but now it's back to crashing big time, I can't get reliably through 5 minutes without it crashing out, and it crashes pretty much when switching from full screen.

I'm on Lubuntu 12.04

I've never been able to get the debug tools to work BTW, matter what I install, which is why you're not getting 20-30 crash reports from me a day.