Got the solution. Calling isc_modify_user creates new connection to the database and "Enhanced ISC4" only allows 3 connections in the minute.
Is it possible to have permanent connection while I'm modifying users?

Riho-Rene Ellermaa
senior programmer
Hansabank

>
> I modified my ISC4.GDB with Ivan Prenosil "Enhanced isc4.gdb" script.
> Now, when I try to modify my users, by calling
> isc_modify_user(...), in 40% of the cases I get error
> 3355...472: "Your user password or name is not defined". When
> I click OK and rerun the function it saves data ok. I looked
> at the parameters I pass to the function and they looked the
> same in both cases.
> I put back the original ISC4 - now it worked OK.
>