Thanks Daniel for your reply.

I just updated to ibo4.3 but the problem still exists.
It only gives me a little different errormessage.
When I use the debugger to show me what is in parambyname
('dateparam').sqltype it shows me the value 496 which meens a integer
value.
The same value is in the sqltype property of the other parameters I
pass to the udf. In that cases it is o.k., because they are integer
parameters.

Why does IBO show me the date parameter as an integer parameter?

When assigning a datevalue to the asdatetime property of the date
parameter, I get an exception that the value is not a valid
integervalue.

cu
Helmut