Specifically, once you are in control panel, can you see info about your characters? If you can do that, then your connection to login server and char server are both fine cause you are able to retrieve information about your characters.
For the error, does anyone have a screenshot of it? On Windows, are you able to fetch Details in the error pop up? What does it say there, if anything?
EDIT: was informed apparently no particular error message beyond "heRO.exe has stopped..." and no buttons to click on for details.
