If Dreamweaver is behaving in an odd way, it frequently means you have a corrupt personal configuration folder. Close Dreamweaver, locate the personal configuration folder, and rename it. When you restart Dreamweaver, it should create a new configuration folder with all the program defaults.
For details of how to find the configuration folder, see this page in the Dreamweaver FAQ.
When Macs lose site definitions, it's often the result of a corrupt keychain. I have never needed to repair the keychain on my Macs, so I don't know the process. However, searching Mac help or Google for repair keychain should point you in the right direction.
To answer Nadia's question about where to export sites on a Mac, it's the same as Windows. Site > Manage Sites. Shift-click to select all the sites listed in the dialog box, and then click Export. Save the .ste files somewhere safe, ready for reimporting later.
Well, it's been an interesting day:(
I did save the settings (thanks for that!) then uninstalled DW using the application disk uninstall feature then started ti install DW. I was instructed to install the 'Adobe ExtendScript Toolkit 2'(?). So I inserted the second disk but, 'Adobe ExtendScript Toolkit 2' apparently isn't on that disk ether...
So... I attached my mac laptop to my mini and transfered DW over but, as you can guess, it didn't work. The s/n wasn't accepted. For anti-pirating reasons I guess.
So... I went back and tried to uninstall the DW copy from my laptop and now I'm getting a set-up error box. 'Setup has encountered an error and cannot continue. Contact Adobe Customer Support for Assistance'.
What's the next step? Is there a way to fix this without spending time on the phone?
You can try the steps in the article on installation issues in the Dreamweaver FAQ. However, it sounds as though you might have created problems with the licensing system, in which case Customer Support is probably your best best.