Hi,
What value are you using with level-2 informix?:

the following values are applicable:

0200 iterative method
0100 nested method
0400 filter method
01000 keystart method

i.e inf_storage file:
*:*:T:group:0200:5:I:INITIAL 16 NEXT 16 LOCK row

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Versions: Informix 9.40.FC5 and BaanIVc4 on hp-ux