apt-get install kinit kio kio-extras kded5
After much searching and experimenting, I was able to find a solution for this problem.
klauncher is a daemon for service activation in KDE and is controlled by
kdeinit supplied by the
kinit package. This package was not installed, so I installed it:
apt-get install kinit
Once I installed
kinit, the error message went away, but was replaced by another error message:
could not start process unable to create io-slave klauncher said: unknown protocol 'file'
After some searching I realized I had to install the KDE Input/Output framework:
apt-get install kio
This solved the problem, but to be sure I also installed kio-extras:
apt-get install kio-extras
I am now able to right-click and save links without issue. I did still get the following error message when running konversation from the command line:
Can't communicate with kded_kcookiejar!
Using @Graham's solution, I was able to resolve this issue:
apt-get install kded5
EDITED TO ADD: There still seems to be one outstanding issue. Even though I can save the links, it doesn't remember the last folder I used. Before I upgraded to 15.04, the last folder I saved something to was remembered the next time I tried to save something.
Now, this is not the case. The "Save As" dialog does not remember the last used directory. Instead, it defaults to the directory I run konversation from.
I'm still looking for a solution for this.