wrong query value while running on VPS

[Karol Wojtyła]

That is very funny. When I run my application on home computer with
windows xp, everything is all right, but when I run it from VPS
(virtual private server shared with other users)
with windows 2003 server , every several queries I get zero (0)
instead of the expected value. Just before the query I set:

var
TD: TTransactionDesc;

TD.TransactionID := 5;
TD.IsolationLevel := xilREPEATABLEREAD;

I am using DBExpress, Delphi 7, Interbase 7,5
and the query is very simple just SELECT COUNT(*) FROM MY_TABLE
and no records are inserted no deleted while testing (just updating;
sometimes there is a concurrent update).

I wonder if anybody has ever encountered such a problem. Could that be
something wrong with my VPS or should I just change my Delphi code or
VPS configuration?