Problem HACMP



We have two 7026-6H1 with AIX 4330-11, HACMP 4.4.1, OPS 8.1.7.4.0. The cluster is configured in cascading (for IPAT) and concurrent mode.
Since last year sometimes one of the boxs halts with the messages in the errorlog:

LABEL: HA002_ER
IDENTIFIER: 12081DC6

Date/Time: Wed Sep 20 05:32:26
Sequence Number: 2242
Machine Id: 000F751F4C00
Node Id: BDCallCenter2
Class: S
Type: PERM
Resource Name: haemd

Description
SOFTWARE PROGRAM ERROR

Probable Causes
SUBSYSTEM

Failure Causes
SUBSYSTEM

Recommended Actions
REPORT DETAILED DATA
CONTACT APPROPRIATE SERVICE REPRESENTATIVE

Detail Data
DETECTING MODULE
LPP=PSSP,Fn=emd_gsi.c,SID=1.4.1.33,L#=1361,
DIAGNOSTIC EXPLANATION
haemd: 2521-032 Cannot dispatch group services (1).

We applied the APAR IY26148 but didn't work.

Any sugestion ?

thanks.