It seems that kdesudo is trying to parse the '--embed-proxy' command line option in this case.
The next natural thing to try was using quotes -- none of the commands work at all with quotes. It seems that they're trying to locate an executable with the name of the entire string or something.
Using quotes on this command line will allow you to reproduce the "Command not found" error.
I was playing around with this a little bit, from the command line the following works:
The following works with sudo:
p@m$ sudo /usr/bin/kcmshell kcm_knetworkcon fmodule --embed-proxy 54527261 --lang en_US
But this fails with kdesudo
p@m$ kdesudo /usr/bin/kcmshell kcm_knetworkcon fmodule --embed-proxy 54527261 --lang en_US
It seems that kdesudo is trying to parse the '--embed-proxy' command line option in this case.
The next natural thing to try was using quotes -- none of the commands work at all with quotes. It seems that they're trying to locate an executable with the name of the entire string or something.
Using quotes on this command line will allow you to reproduce the "Command not found" error.