I get a similar error message on Ubuntu Wily.
It looks like libkdecorations4abi2 was part of kde-workspace, but this package has been removed from Ubuntu 15.04 and later releases, and been replaced with plasma-workspace[1].
[1] See the removal request for Vivid at https://launchpad.net/ubuntu/+source/kde-workspace/+publishinghistory
I get a similar error message on Ubuntu Wily.
It looks like libkdecorations 4abi2 was part of kde-workspace, but this package has been removed from Ubuntu 15.04 and later releases, and been replaced with plasma- workspace[ 1].
[1] See the removal request for Vivid at https:/ /launchpad. net/ubuntu/ +source/ kde-workspace/ +publishinghist ory