The file to delete to remedy this error is the "LauncherUserSettings.xml" file, to do so perform the steps below:
Thanks go to Mutantbee for the catch and reminding me of some ommited folders
- To start first close out of the launcher if its open (right-click the ddo "shield" icon near the Windows "clock")
- Now click on the Windows "Start" button and click on "Computer" or "My Computer"
- In there double click on your "C:" Drive (Might display as "Local Disk C:")
- In there double-click on "Users" if you are on Vista/Windows 7 or "Documents and Settings" if you are on XP.
- In there double-click on the folder that is the same name as your XP or Vista/Win7 Username (as an example if when you log into your computer you log in as "Bob" then look in here for a folder named "Bob" as well)
- In there you need to enable hidden files and folders view:
- - XP: Click on "Tools" > "Folder Options" > "View" (tab) > click to activate "Show hidden files and folders" in the list
- - Vista/7: Click on "Organize" > "Folder and Search Options" > "View" (tab) > click to activate "Show hidden files and folders" in the list
- Now once that is done you should see "Local Settings" if you're on XP or "AppData" if you are on Vista/Win7 double click on that
- In there you should see either "Application Data" (XP) or "Local" (Vista/7) double-click on that
- In there find the folder "Turbine" and double-click on it
- In there double-click on the "Dungeons and Dragons Online" and then the "Launcher" folder
- Now find "Launcherusersettings.xml" and right-click that and choose "Delete" then relaunch the game
EDIT: It's come up a few times so I wanted to add: If you cannot find the "Launcherusersettings.xml" file or you still get the error after deleting one, most likely you might have gone into the wrong folder at step 5 up above.