onbar error -43207 on IDS 11.50 FC1

We are trying to setup onbar on a new IDS 11.50FC1 server.

on issuing the command

onbar -b

we receive the following error in bar_act.log:

2008-08-08 15:37:35 21972 21970 /opt/informix/bin/onbar_d -b
2008-08-08 15:37:35 21972 21970 (-43207) Unable to open connection to database server: IBM Informix Dynamic Server Stopped..
2008-08-08 15:37:35 21972 21970 /opt/informix/bin/onbar_d complete, returning 151 (0x97)

But the server IS up and running.

We have set BAR_DEBUG to 9 and get the following in bar_dbug.log

2008-08-08 15:37:35 21972 21970 bar_srv_status: enter
2008-08-08 15:37:35 21972 21970 bar_srv_status: return -1 (0xffffffff)
2008-08-08 15:37:35 21972 21970 bar_main: server status -1

Tried the same in quiescent mode: same results

Any ideas?