Can we use the editor with phpbb3?

I mean you can use the editor with any application. The thing is you will have to write the code into your PHPBB template. If you can do that, then it will work.

I mean there are none. You need to figure that out for yourself using the samples, config API, the PHP CKeditor loader class (ckeditor.php), google, and basic knowledge of PHP (The main thing is editing PHPBB, they have great documentation though so shouldn't be too hard to find where the post editor is created). The version doesn't matter, you can use whatever suits you. Use CKEditor though one of the new versions.

Because I understand how the underlying code works. I guaren-friggen-tee you that it will work because why wouldn't it? CKEditor is Javascript. PHPBB is PHP. It's not a matter of them conflicting with each other because they are seperate languages and seperate functions. The problem which might make it complicated, however, is that you would have to find exactly where in the templates the editor area is output and replace it with CKEditor code, then you would also have to ensure that the data is returned in the proper format to PHPBB, finally, you'd have to mod all of the output to be BBCode.

I don't know the historical aspect of it, but if it really was three years ago as you claim then CKEditor has been developed since then (I.E. That forum was for FCKEditor). It should be much easier to use the htmlprocessor to custom format the output into BBCode, at least the basic stuff in CKEditor.

I know that it works, because of the theory behind it. It's simple. The problem is getting the elbow grease required to integrate it and work out all the bugs. People using Drupal and CKeditor are constantly asking questions here which are not errors with CKEditor but rather errors with either the intergration process or their particular installation.

Such would inevitably be the case with PHPBB, but I promise that if you spend enough time ripping everything apart, you could make it work.

You just posted your own tutorial. As you can probably see, it's really hard. I'll try to give an overview of what you'd have to do.
Obviously remove all those editors files and put the CKFiles somewhere.

1) Hardest: Start by looking at the installer XML. These installers in PHPBB are simply a list of commands like:
Open File #1
Find 'Do part a'
Add-After 'Do new thing after a'
You have to look at each of his entries and figure out what he's doing and if it needs to be changed for CKEditor. Including the new paths

2) Modify files until you get it going with the basic settings, it doesn't have to submit code, just have to get the instance of CKEditor going and then your on the home stretch.

3) Change CKEditor to fit BBCode style by modifying the dataprocessor and htmlprocessor and all.

Since he added an editor, you are going to be modifying basically the same files. You just need to use the CKEditor PHP Syntax. The problem, now that I think about it, is that it looks like his does too much. I think you can do a lot of the php code he's doing (Conversion of BBTags) through CKEditor by defining the style formatter as such. However, since there are so many complex tags possible, you might end up needing some of this code. I don't know.

Again, if have read any topics on this, you'll see that it is not at all a simple process. As evidenced by how complicated all the code is. Nevertheless, it can be done. Good luck.

EDIT: Maybe see what this is too: http://www.meis2m.com/upload/uploads/phpBB3.rar