CF 7 with Dreamweaver CS3

My setup is:-

DW CS3

CF MX 7

Windows 7 workstation

Windows 2003 development server

Local area network

I am having a problem with DW CS3.

A site I have used for some weeks has suddenly started misbehaving.

When trying to access a CF 7 data source binding I get :-

"In order to view the columns of this recordset, please associate the variable (#application.dsn#) with a data source.  To do this, press the plus button and choose Data Source Name Variable."

When I try and associate my application.dsn with a data source none are seen in the drop down.

I compared the site to another site which is working fine and I can't see any difference in the setup.

I have cleared the site cache and removed the data connections from within DW. (menu, Site => Advanced)

I tried completely recreating the site copying only the cfm files into a new directory.

I tried removing the configs from the Appdata cache/config.

I tried reinstalling Dreamweaver.

I've used this set up for years, but that doesn't mean to say I haven't missed something obvious - very rusty.

Any ideas as to what is wrong, please?

Thanks,

Jenny