^^^^^^^^^^^^^^^^^^^^
This is the 'key' if you'll pardon the pun.  IDS creates several shared
memory segments using keys that are calculated off a base value (0x52564800)
plus 0x00010000 time the SERVERNUM (in your case zero) plus the segment
number.  So the first segment for your server (the RESIDENT segment) would
be keyed as 0x52564801 and the key 52564803 is the third segment or second
virtual segment.  Apparently either this key clashes with another
application's use of shared memory key values or there was an old segment
left in memory the server crashed or was taken down previously.  Use ipcs to
determine the owner of the segment.  If it is an IDS segment it will be
owned by root or informix (version dependent) and group informix.  If not,
you can change the SERVERNUM in the ONCONFIG file to change the key range
IDS uses so it no longer clashes with your other apps.  If it IS an IDS
segment left over, first try running 'onmode -ky'.  This will usually remove
old shared memory segments and semaphore groups.  Otherwise use ipcrm to
kill the segments manually.

Art S. Kagel