Thank you Helen,

You triggered me with your remark:

>Now, since this is an IBO error dialog, the actual error could
>be coming from an illegal OrderingItem somewhere in the statement's
>setup...

I wrote the SP using IBOConsole. An IBO based clone of IBConsole.
When I try my example in IBConsole it works OK.

So it's either IBOConsole or IBO, but not Firebird.

Again thank you,

Henk van der Meer.