[gdal-dev] GDAL thread safety

[Even Rouault]

> The proper
> solution would be to fix CPLOpenShared() to be more thread-friendly (that
> is to say to return different file handles if called with the same
> filename from different threads)
> 

Should be fixed by ticket http://trac.osgeo.org/gdal/ticket/4848 that should go 
into GDAL 1.9.2RC2. I didn't test your scenario but anyway CPLOpenShared() was 
the likely cause.