SQLHOSTS server group entries.
 To remedy this problem, pursue the following options: sqlhosts file, e.g., sqlhosts2 .
 (This second sqlhosts file cannot contain server group entries.) Then, set the INFORMIXSQLHOSTS environment variable to point to this new file.
 For example: 
export INFORMIXSQLHOSTS=/dbs/informix/32bit/7.3/etc/sqlhosts2
sqlhosts file.
$INFORMIXDIR/etc/sqlhosts  file (or the sqlhosts information in the Windows registry) should be checked, to confirm that all data therein is correct and contains supported values.
DBSERVERNAME, DBSERVERALIASES, and NETTYPE parameters in the $ONCONFIG configuration file or within the informixserver entries in the registry.
dbservername, nettype, hostname, and servicename fields in the sqlhosts file to make sure that you have entered the correct values.