Problem using index files on Unix

[Olivier LAFIT]

Hello,

I am using index files (.qix generated with shpTree) to display quickly
shapes.
It works fine with Linux and Windows, but with Unix my MapServer failed to
draws the shapes : the main map is correctly displayed, but when I zoom in,
shapes disappear, and I get only the background.
Every things works when I delete every index files, but slowly...

I'm using MapServer 4.2.5 and UNIX : DEC Alpha. OSF1 5.1.

Does anabody have an idea ?

Olivier Lafit