There is no script availible for, but you can write your own skript.  You must know it is different to all Forums by design, so wie can't write scripts for all existing forums.  But you are free to write your own scribt.  You can find a SQL Documentation on www.dnnforums.com .

I have posted you find all database tables and the database design on www.dnnforums.com . You have to import all user data, userID, posts, threads, permissions, user profile ect., but you can't do it with out sql knowledge.  We can't help in that, about is to differnt how the datas are saved between DNN Forums and other Forums.  I suggest to look to the Forum databases and then look what your forum have saved, and what do the dnn forum save.  Perhaps you have to done some chnages about the different work of the databases.   It's not easy to move the data from a other forum to the dnn forum.  And my help is restrit, about I do not know of your existing forum.