Spatial Analyst - Zonal Statistics error related to 9.3 SP 1?

Discussion created by Janotto on Apr 22, 2010
Latest reply on May 25, 2011 by robertcolombo75
I have the following problem using Zonal Statistics in SA, 9.3 SP1:
When calculating zonal statistics for a polygon, the resulting table misses some values. Consequently the joined tables (zone dataset and output table) do not match and some field are populated with <Null>.
I have used an simple numbering (1-8400) for the zone field, but some number in the output table are left out.

The problem is especially annoying, because I use this function in a GIS course that I teach. I prepared the exercise on my laptop using the single use license of Arc GIS desktop 9.3 without service pack (SP) 1. However during the course at Uni and on my office computer this error occurs. So, I believe that this has to do with SP1.
Did anyone come across this issue as well?
I feel pretty bad as a teacher, with these things occurring in my courses.
Any help is gratefully appreciated!