Hello list,
I'm back again to report what's happend.

First of all I want to explain how the system works.
There are two main apps: OA (Office Automation) and WA (WorkShop
Automation) and an auxiliary one AM (AutoMAN):
OA cares about Client's Orders
WA cares about internal/external production problems
AM registers ManWork cycle times.
The DataBase ( IB 6.0.1.6 ) contains 108 tables and various procedure.
All are built with Delphi 5.1/IB 3.6Di using native IB_ components
The hardware is: 1 Server and 5 Clients, all with Windows 98 II
edition.
DataBase clearly resides on Server.
OA and WA reside on Clients and only AM resides on Server.
The system was upgraded from DBF tables and is working from 3 years.

The fact.
---------
Yesterday, meanwhile I was making some training to personnel on a
Client, appeared the message "Fetching Query Result", but we are not
changing any data.
Again, after few minutes, making a new Report ( Report Builder ) the
same message and the report project closed itself!!??
After some investigation on the activity on other Clients/Server I
saw only AM was working on the Server. The application uses an
IB_Connection, an IB_Transaction ( isolation = tiCommitted ) and
various IB_Query and IB_DSQL.
The application has only two procedure:
start working - register the time
stop working - register the time and calculate cost etc. etc.
If needed I can send the start / stop procedures.
Please note that also making a new Word doc, same message ( "Fetching
Query Result" ) appeared.
Nothing appears on other Clients.
-------------------------------

Any ideas?
Can suggest further "investigation"?

Thanks and rgds.
Paolo Fenelli / AC SOFTWARE HOUSE - NAPLES