Problem with expression engine

Hi

I encountera problem with this expresioon:

iif(ANZKONTROLLIERT12 > 0, ANZFEHLER12 * 10000 / ANZKONTROLLIERT12 , 0)

I try to create a index via _ADSCREATEINDEX61 and this index key.I get an error

4020 Division by zero in index key expression

which should not be possible.

Both fields are of type integer and there is no NULL value, but one record with ANZKONTROLLIERT12 is 0. I tested with Vers. 11 and 12, both fail to create an index. It works fine, when there is no 0 record.

Anyone any ideas or is there a problem in the expression engine?

Regards

Marcus