Classfier::no-slot{} error

Hi
I am simulating a wired-cum-wireless topology (with hierarchical adressing), with multihomed SCTP agents on the endpoints.
I have this error exactly when the traffic is starting :

Classfier::no-slot{} default handler (tcl/lib/ns-lib.tcl) —
_o94: no target for slot 0
_o94 type: Classifier/Hier
content dump:
classifier _o94
0 offset
0 shift
2147483647 mask
0 slots

---

Finished standard no-slot{} default handler

---

The classifier _o94 corresponds to the sender SCTP core node entry (MH_core).

The endpoints are defined as follows :

set sctp0 [new Agent/SCTP]
$sctp0 set-multihome-core $MH_core
$ns_ multihome-add-interface $MH_core $MH_if0
$ns_ multihome-add-interface $MH_core $MH_if1
$ns_ multihome-attach-agent $MH_core $sctp0

$sctp0 force-source $MH_if0

$sctp0 set usNumStreams 2 ;# nb streams =2
$sctp0 set debugMask_ -1 # u can use -1 to turn oneverything
$sctp0 set debugFileIndex_ 1
#$sctp0 set heartbeatInterval_ 1

set trace_ch [open trace-infra9.sctp w]

$sctp0 attach $trace_ch

set sctp1 [new Agent/SCTP]
$sctp1 set-multihome-core $CN_core
$ns_ multihome-add-interface $CN_core $CN_if0
$ns_ multihome-add-interface $CN_core $CN_if1
$ns_ multihome-attach-agent $CN_core $sctp1

$sctp1 force-source $CN_if0

$ns_ connect $sctp0 $sctp1

$sctp0 set-primary-destination $CN_if0
$sctp1 set-primary-destination $MH_if0

Can you tell me what is the problem?
Your help will be really appreciated.