Let's get one thing straight first: did you install "im-switch" ?
If you did, then go on reading my article.
If you are didn't, then maybe my article is not what you need.
If you just install im-switch, and you found that you can't login into LMDE anymore
here comes the answer:
2.login into text mode
3. type in following command:
sudo apt-get remove im-switch im-config
4. After step 3, type in :
sudo apt-get install im-config
5. reboot, and weeeeeeeeeeee