Acrobat Professional 9 error merge multiple files into one file

In  the same file I made the text boxes and then I have produced more than  one file, I then tried to merge into a single file but the software  copies the same pages of the first file.
Let me explain:
1) in the first file number 1 I have 3 pages, these pages I have text boxes and then I saved the file with no 2, then No. 3, then 4;
2) I took the first file and the file I downloaded in the last 2,3,4
3) I opened the software to control and I copied the file multiple times n. 1 just
4) so ​​now I have to file a repeated 4 times in a single file.

What should I do to be merged into a single file as separate files?

Perhaps  this warning is that you understand the problem, since I used the same  page by giving it a different name just because I made some text boxes  with different content, that is, the program identifies the file and  then continues to quote the same as another copy the same file, then I should change the form field for each file. How should I proceed?
Of course I followed the instructions of the notice but the thing has not changed, all the files you copy the same.
I enclose a picture