I have a problem with my excel add-in which works fine for earlier versions
of excel - but does not work properly with excel 2007. The OP system is
windows XP.

The code to connect is as follows:
Public cs_dbs As Database
Set cs_dbs = OpenDatabase(dbName, False, True, "ODBC;Regional=Yes")

When dbName is empty (as it will be for a new file), the user will be
prompted to select an ODBC source. After I select the source I get the
following error message: Cannot open MyDB database. Error: ODBC--connection
to 'MyDBSQL2005' failed.

If I look in the odbc trace log, I will eventually see the following error:
DIAG [S1000] [Microsoft][ODBC Driver Manager] General error: invalid window
handle.

Trying to connect to a Progress database, also ends in failure after I
select an odbc source. In this case I should see a window prompting me for a
password but I just get the error message that the operation was cancelled by
the user.

BUT: The following will work:
Public cs_dbs As Database
Stop
Set cs_dbs = OpenDatabase(dbName, False, True, "ODBC;Regional=Yes")

In debug mode, I can connect to both DB types. The odbc trace logs show no
errors.

It could be a bug in Excel 2007. This add-in works in earlier versions of
excel and works in debug mode in excel 2007.
AND if I open an existing excel sheet which already uses the add-in, then I
can connect without problems to the database. The DB is opened automatically
& formulas are refreshed.

Does anybody have any clue what is going wrong here? I hope I have provided
enough information.