1) Error -10646 means the DAL client cannot load the Network Adapter. You probably have the wrong driver installed. MacIrma is shipping with the HLLAPI drivers, which DAL doesn't support. You need to call DCA and get the Apple API drivers. Apple does not have the rights to distribute them, so you have to get them from DCA.
To verify this, the following files should be in the system folder:
DFT: "MacIrma SNA 2.1.0" (or .1) and "MacIrma DAL Driver" 1.2.0
CUT: "MacIrma DAL Driver" 1.2.0
In addition, be sure that your coax line is correctly identified as CUT or DFT in you DAL connention script.
2) Once a session is established between the DAL client and the DAL server, the server will be ready to accept any request from the client. Perhaps an explanation of DAL Request/Reply relationship would help:
DAL uses a request/reply relationship between the desktop and the server(s). The user connects to the host machine using the query tool (HyperCard, 4th Dimension, or a custom C or Pascal program). The query tool application passes the request to the DAL API, which in turn establishes a connection to the host server. The DAL server on the host receives the request and translates it to the SQL dialect of the opened database. The server then checks the syntax and passes the translated request to the proper database. The database complies and passes the data back to the DAL Host Server. The Host Server checks for errors, mapping them to the standard error set that DAL supports. The server then assembles the results returned from the database sends them to the Macintosh. The query application sees the results are available and begins to put them, item by item into its own window (such as a spreadsheet window).
3) DAL provides Application Programming Interfaces for C, Pascal, and HyperCard.