Thank you for your response.

>>The nature of errors is the following - one of record's

backversions is missing, and Firebird cannot read >>chain of back versions to build actual (yours) version of this record.

>>The reason "wrong transaction management", I think, is not

correct, and we will change it - usually this >>happens due to hardware problem in RAM or disk.

I hardly belive that this is the problem of RAM or disk, because the same problem (on the same table) happened in two different clients in simmilar time. So, lets rule out problems with hardware and lets rule out problems caused by power outage and we are left with what...? Bug in Firebird?

The table which is causing problems for us has been added lately. Also there is one trigger on different table which is fired on insert/update and it is inserting data to the problematic table. I do not know if this trigger is causing the problems tho.

So I have two clients, the same problem on the same table and I have no idea what is causing this error...