[ns] ns2 tcl problem

i have this error what can i do??

--- Classfier::no-slot{} default handler (tcl/lib/ns-lib.tcl) ---
_o12: no target for slot -1
_o12 type: Classifier/Hash/Dest
content dump:
classifier _o12
0 offset
0 shift
1073741823 mask
1 slots
slot 0: _o722 (Classifier/Port)
-1 default
---------- Finished standard no-slot{} default handler ----------
lala@ubuntu:~/ns-allinone-2.35$ ^C
lala@ubuntu:~/ns-allinone-2.35$ ns network.tcl
--- Classfier::no-slot{} default handler (tcl/lib/ns-lib.tcl) ---
_o12: no target for slot -1
_o12 type: Classifier/Hash/Dest
content dump:
classifier _o12
0 offset
0 shift
1073741823 mask
1 slots
slot 0: _o722 (Classifier/Port)
-1 default
---------- Finished standard no-slot{} default handler ----------