Try recreating the Users configuration. that is the configuration folder that contains the dat file.
close DW, locate the users configuration folder and rename it to configuration_bak.
when you open DW, it will be recreated.
you will need to reinstall extensions after doing this.
Close DW, open the extension manager, remove the extensions, then install them again.
When installing the WebAssist Extensions, make sure you have the most recent versions.