Some other forum members and myself have had "Could not connect to wicd's D-Bus interface." pop up when starting X. The log, however, shows no errors. Enabling network start on boot solves the issue, but can be annoying to some of us. I've found a simple workaround that removes the error without starting the network at boot.
Move wicd-tray.desktop out of etc/xdg/autostart and place it somewhere else if needed later. Now when starting up, the error will be gone, but will pop up again if you start wicd-client or wicd-gtk. To prevent this, networking has to be enabled first.
To start networking and the wicd gtk interface in one click, you can right click on the Services>NETWORK>"WICD gtk interface" selection and select "edit item". Then change the command to:
Now the error's gone, networking doesn't start at boot, and wicd is enabled with one click
sh -c "start-network && wicd-gtk"