When trying to preview data, I'm getting a Dreamweaver error saying "A server timeout has occurred." As the message suggests, I've checked to make sure that my Web server is up and running, and that there is an ODBC DSN on the testing server. What next ?
You may get a timeout when there is a lot of data in the table you're trying to preview.
First, try viewing another table that you know has less data in it. If you can view that table, then your database and DSN are working properly. The problem could well be a table with too much data in it.
The best solution, which will allow you to work more efficiently and reliably here and elsewhere, is to use representative sample data for development, with no large tables.
Other possibilities are
Build your own query in Dreamweaver and view the data in the browser.
Use the appropriate database management system, such as Microsoft Access, to view the data.
Increase the Page Timeout and/or Max Buffer Size for the DSN, using ColdFusion Administrator, Data Sources, Edit (button on the far left), Show Advanced Settings.