transactions in DLL

Hi,

  I have a little client program that uses a db interbase placed on a
server.
 Normally I have two or more copy of this client placed on different pc
 that uses the same table .

The program is made of two modules:
  1) a principal form that shows a grid with all the records of the table,
      with a button marked as 'edit' that runs...

  2) ...a second form contained in a DLL, that i use to show and edit data
from table,
        one record at time.

The problems:

1) I want to share db, db connection, and table betwen then main application
(that makes connection and shows a DBgrid) and the second form contained in
a DLL.

2) Then I must use transactions in this second form, cause I can have two or
more copy of the
program working in concurrence by many users, and i must be informed if
someone makes
a lock on a record of the table modifyng data.

3) I know I must pass the handle of the db to the dll and than assing it to
a new DB,
I read also an example to syncronize tables from Borland, but every time i
try to
use db.starttransaction i obtain an error .

There is a way to do what i want to do with those components i described  ?
(I don't know difficult instruments like run time packadge, midas, dcom,
ecc.)