Creating random wired topology for given arbitrary number of nodes on NS2

I want to create and simulate a wired topology using NS2. Trying to write a tcl and positioning the nodes and links using rand() . My solution was this But the randomization is often creating erroneous links and thus problem in simulation and getting this error :

--- Classfier::no-slot{} default handler (tcl/lib/ns-lib.tcl) ---
_o28: no target for slot 4294967295
_o28 type: Classifier/Hash/Dest
content dump:
classifier _o28
0 offset
0 shift
1073741823 mask
1 slots
slot 5: _o268 (Classifier/Port)
-1 default
---------- Finished standard no-slot{} default handler ----------

But this is also random and does not occur always. When it does not occur , the nam file shows that there have been duplicate definition of nodes. Can someone please just give me some guidance about how to create a random wired topology with random valid links?