arcgis desktop - Self intersections for polygons, how to solve?

I have a question about repairing a self intersecting polygon shapefile. I have a shapefile containing Polygons (ZM) which have self intersecting features. If I use the "repair geometry" tool, it finds several self intersections and fixes them. Hurray!

But when I make an export of this file (or a selection of it), this export contains self intersections again. This happens on all the tries I've done to handle the problem, which include:

1. Use the tool "repair geometry", failed;


2. Dissolve the polygons based on all of their attributes, failed;



3. Dispose of the ZM properties, and then do all of above, failed;

Even when I import this shapefile into an Geodatabase using ArcCatalog, it imports correctly, but when I make an export from the database, the self intersections are there again.

So any advice on how to fix this problem would be very much appreciated. If anyone could explain why this type of behaviour exists, it would be wonderful.

I'm using ArcGIS 9.3.1 build 4000 (SP2).