The problem may be with packages and ports on your already system. Delete the program, then remove distfiles through the make command. Make clean, make rmconfig-recursive. Update src and portsnap. Make sure they're the right ones. Then, try again. [someone pointed out ports weren't being used] -> I was thinking about another recent thread, where someone was trying to update source to compile or use a package for a graphics kmod. It could explain for any program using ports, but that wasn't the case.
But about the mounting and executive permissions, that was for this thread.
Then, it's a typo in the configuration, lack of configuration or a missing package. That or a bug.
You'll have to give more information on what's going on. It may take a little research and looking at log files, and dmesg messages etc. People here are guessing on a wide range of what it could be, and you'll have to narrow it down.
I have used Arch Linux, other Linux and program specific documentation to configure programs on FreeBSD before. KDE and SDDM independent documentation would be relevant. Then I use the documentation here for what's more specific to FreeBSD. Or for those more familiar with KDE on FreeBSD, they would be able to answer SDDM questions better.
