i add a video to the Project Bin, right-click on it, click on Stabilize (videostab2) in Clip Jobs, and nothing happens. what's wrong?

Kubuntu 16.04, KDENLiVE 15.12.3.

Do you get some output if you start kdenlive in a shell from command line and stabilize the clip?

$ kdenlive
Removing cache at "/home/user/.cache/kdenlive-thumbs.kcache"
QXcbConnection: XCB error: 8 (BadMatch), sequence: 14286, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 14302, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 14384, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 14466, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 14515, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 14564, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 14643, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 14692, resource id: 29360338, major code: 130 (Unknown), minor code: 3
KSambaShare: Could not find smb.conf!
[swscaler @ 0x7f72d8d5bf00] Warning: data is not aligned! This can lead to a speedloss
"Creating audio thumbnails (1/1)"
QXcbConnection: XCB error: 8 (BadMatch), sequence: 56040, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 56123, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 56137, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 56162, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 56191, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 56211, resource id: 29360338, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 56227, resource id: 29360338, major code: 130 (Unknown), minor code: 3

and when i close the program:
QCoreApplication::postEvent: Unexpected null receiver

Did you install the optional package dependency from mlt: vid.stab (from http://public.hronopik.de/vid.stab)?

dvdauthor, dvgrab, frei0r-plugins, genisoimage, recordmydesktop, swh-plugins, khelpcenter are recommended and not installed.
libmlt++3 and libmlt6 are among required and installed.

Alright... You checked the optional dependencies of kdenlive.

So, if you also check the dependencies of mlt, you will find vid.stab as a optional dependency. Is that package installed? You will need it to stabilize your videos in kdenlive.

libmlt6 doesn't depend on anything like that. instead, it installs libmltvideostab.so among other things. so i had it installed yet couldn't stabilize my video.

OK, let's land the thing... I have my information from here:
http://bernaerts.dyndns.org/linux/74-ub ... lt-vidstab

In addition to that, you may want to check this ppa, that is often referred in this board. It provides kdenlive with all components needed: https://launchpad.net/~sunab

On the kdenlive-release page I find a vid.stab package:
https://launchpad.net/~sunab/+archive/u ... ve-release

Obviously it is difficult to help you out from an Archlinux perspective on kdenlive. That is why I am out here...

Good luck!

okay, the following has worked for me:

sudo apt purge kdenlive-data libmlt6
sudo add-apt-repository ppa:sunab/kdenlive-release
sudo apt update
sudo apt install libmlt6=6.0.0-0ubuntu0~sunab~xenial1 kdenlive-data=4:15.12.1-0ubuntu0~sunab~xenial1 kdenlive=4:15.12.1-0ubuntu0~sunab~xenial1

now instead of Stabilize (videostab2) i've got Stabilize (vidstab) which opens the Stabilize Clip dialog.

thank you, capslock, for your interest in my problem and helpful hints.

You are welcome. Glad to get this solved.