The error itself indicates that the core is not compiled with SSL support, but the commands.so module is.
Perhaps a forgotten 'make install' or copying of the src/ircd binary or something like that?
Otherwise, try a 'make clean; make && make install' and see if that helps.
Right. That means ssl_get_cipher is present in the binary, which means that the error should not occur.
Did you install UnrealIRCd to a specific directory (like: not using the source directory as your "running/installation directory"), if so, I suggest you to doublecheck that the 'ircd' binary is indeed the newly compiled one (like: by checking the date/time of the file), etc..
You can find out your installation path by doing a 'grep DPATH config.settings'