I do not know what the error message is about.
As for changing the default workspace:
1) Choose File > Switch Workspace > Other
The Workspace Launcher dialog appears.
2) Type in the path and name of the desired Workspace folder, or Click Browse and navigate to the desired folder.
3) If you want this change to persist, check the "Use this as the default and do not ask again" option.
4) Click OK.
---Tom