'Suppressing of zero values' will be disabled when using certain functions, like the rank().
It seems that there was a change in recent version (not in your 10.00), that handles at least NULL values differently (maybe also zero values). I believe that's why settu, Sunny and myself can't reproduce your issue on our machines.
I am not 100% sure if the change was also documented, could you post your 10.0 documentation line for that Note! I've posted above (just look into the Help for rank(), this line should be top of the page)?
I also believe it has nothing to do with NULLs in the rank function, but returned NULLs and zeros and usage of the 'supress zero values' feature.
Sorry, if this is getting complicated.
You said, on server side it's KO, too. That means it's not working, right? Same 10.00 version on that server?
Any chance to test on a more recent major version?