Uhm. I've tried 7 times at this point, adding possibly silly variations after the initial standard try —things like closing Extension Manager each time after the two installs, or restarting the computer.
I tried removing a non-WebAssist extension, and doing the WebAssist installs several times. Made no difference.
My method exactly was:
1) Uninstall all extensions
2) Rename the configurations folder
3) Install Deprecated Server Behaviors 1.0
4) Open DW then quit DW
5) Install eCart6 first, then DataBridge 1.1.9 second —one immediately after the other
6) Open DW and watch the install finishes. Quit DW.
7) Reopen DW. Try to use a WebAssist product within DW.
I have DW preferences to open php pages by default.
Can't think of any other details. What should I try next?