Thanks for that link. Would never have found it alone.
I've run some tests with fpc 2.7.1. For now, no crashes anymore.

Am 13.06.2013, 08:58 Uhr, schrieb hvlad <hvlad@...>:

> --- In firebird-support@yahoogroups.com, Vitali Voroth wrote:
>>
>> Hi!
>>
>> I'm not sure if the following is a bug, so i try it here first before
>> posting it to
>> firebird-devel. Chances are that somebody on this list can help me.
>>
>> I am running the 64-bit version of Firebird 2.5.2 (26540) on Windows 7.
>> I noticed that the server crashes after using a udf compiled with
>> FreePascal,
>
> Unfortunately, FPC for Win64 contains a bug with exceptions handling.
> See
>
> http://mantis.freepascal.org/bug_view_page.php?bug_id=17360
>
> Vlad
>
> PS looks like it is finally fixed in FPC v2.7.x
>