Welcome to LQ!
I have no idea what "NCTUns-4.0" is, but there'll be an executable file somewhere
if it installed OK.
Perhaps it hasn't installed a link to your menus.
If you are running the KDE desktop, try this:
R-Click the Start / Launch / K button (Its name depends and I do not know Fedora)
Choose menu editor.
Then just do file .. Save.
Your menu will be re-populated.
Is it there? Somewhere?
Otherwise try (as root) updatedb
to update the locate
database. This may take some time. Be patient.
Then locate nctuns | grep bin
should tell you where the executable lies Eg /usr/bin/nctuns
If so, try running it from a terminal (as yourself
as root) as /usr/bin/nctuns
or whatever the path you have found for it is.
If that works, you can then add it to your menus with the menu editor.
I did a quick google for "nctuns" - only 925 hits, and mostly problems