Multiterm 2015 doesnt work after install some API. Can someone help me please?

I have install some API two days ago and since there MUltiterm 2015 has stopped to work. I have tried to uninstall it and install it again but nothing. Everthing is blocked. Please can someohne help me??? I have freelance plus and i have already use the two licence. Sorry for my english, i speak better german. Thank you for your help!