You need only to rename/delete the folder C:\Users\YourUsername\AppData\Roaming\eM Client or if you use XP, C:\Document and Settings\YourUsername\Application Data\eM Client and then import again properly.
I’m having a similar problem and uninstalled the program, but when I try to reinstall it, it picks up the account I don’t want. I can’t find the above folder under 'users". Am new to Win 7 (as of today). Would these hidden files be somewhere else?
Thank you.
Directory AppData from the path C:\Users\YourUsername\AppData\Roaming\eM Client is hidden, you will need to set your files explorer to display you hidden files also.