Can i stored iMovie projects and files in an NTFS external drive? I'm backing up manually my computer with the data I want to keep.

I've already backed up iPhoto library in a a Mac OS Extended (Journaled) partition as it seems is the only way to store it properly. 

They say that it involves other softwares and some internal databases.

I was wondering if it happen the same iMovie or on the other hand, it is just a group of folders and files. (as I believe it is in this case)

Could I use my NTFS external drive to backup iMovie files and folders? (projects and events folders)

I'm using Mac Os X 10.6.8 and I'm updating to Mavericks. 
I'm using Tuxela NTFS to be able to write and read NTFS from my Mac.
I'm using iMovie 11 9.0.4
Yes you can. Since you have Tuxera NTFS installed, you are able to read/write to the drive fine, so iMovie will have no problem saving to it. iMovie projects aren't as complex as iPhoto libraries, so you shouldn't have any problems.