At the moment, I don't believe there is a script to automatically convert phpBB3 to Icy Phoenix. If you are savvy enough with databases, you could try converting your database tables manually. Be aware this will take some time depending on your board size. The most important tables to move over would be topics, posts, users, forums, etc.
If you don't have many users or posts, you should seriously consider starting fresh as this will save you some major heartache. When I reverted from phpBB3 to Icy Phoenix, it took me days just to sort out my database tables. You'll need to know how to structure everything. It would also be smart to revert from phpBB3 to phpBB2. After you downgrade your phpBB software, updating to Icy Phoenix will be a breeze.
As always, we're here to help and we'll help you to the best of our ability. If you do need help, please be super patient for a response.
Lastly, I'm glad someone sees Icy Phoenix is just as stable as phpBB3. Icy Phoenix has tons of features already built in that phpBB3 doesn't have.
that is a way to solve your question
but there is a other way when you haven't the experience to do this:
is it possible that you can pay for this service?
MG can do this job, please read this careful >>
http://www.icyphoenix.com/viewtopic.php?f=38&t=5097
but this should be the
last option when you fail