Be explicit about the path; there is also /usr/sbin/radiusd in base.

Index: doc/README
--- doc/README.orig
+++ doc/README
@@ -120,7 +120,7 @@
   detailed and clear description of the problem, together with
   full debug output from FreeRADIUS, obtained by running
 
-    radiusd -X
+    /usr/local/sbin/radiusd -X
 
   Developers only discussion is to be had on the devel list:
 
@@ -166,7 +166,7 @@
   the server, then run it in debugging mode, as root, from the
   command line:
 
-    # radiusd -X
+    # /usr/local/sbin/radiusd -X
 
   It will produce a large number of messages.  The answers to many
   questions, and the solution to many problems, can usually be found in