Informix Installation Crashed

When trying to install IDS 7.3 on SCO Openserver Release 5, I am getting following error continuously ... can any body help where should I do??? In fact the "Setup" hangs, when "Launching sysmaster database ...", and then it crashes. Early response will be highly appreciated. Thanks Sm/... 16:14:18 listener-thread: err = -956: Client host or user (informix@katina.aku.edu) is not trusted by the server. 16:14:18 Error building 'sysmaster' database. 16:14:18 See '/tmp/buildsmi.20484'. 17:39:25 INFORMIX-OnLine Stopped. Wed Feb 28 17:41:05 2007 17:41:05 Event alarms enabled. ALARMPROG = '/u/usr/informix/etc/log_full.sh' 17:41:10 DR: DRAUTO is 0 (Off) 17:41:19 INFORMIX-OnLine Initialized -- Complete Disk Initialized. 17:41:19 Checkpoint Completed: duration was 0 seconds. 17:41:19 Dataskip is now OFF for all dbspaces 17:41:19 On-Line Mode 17:41:19 Building 'sysmaster' database ... 17:41:22 listener-thread: err = -956: Client host or user (informix@katina.aku.edu) is not trusted by the server. 17:41:23 listener-thread: err = -956: Client host or user (informix@katina.aku.edu) is not trusted by the server.