This is just to maintain a registry
and
You don't have problems with your project.
This is the procedure for the bug
-Start a brand new project.
-Create a tiled background.
-Save the project in folder.
-Close C2.
-Open the project.
-Create another texture.
-Save it in CAPX file.
-Save in folder but on new clean folder, not the first one, for example.
Check the texture folder, it's missing the first texture and there is only the second, added while the software is running.
It missed to import to the CAPX the pre existent textures and saved on the CAPX only the new texture added when you opened it.
Close the project and try to open it again, it will give you an error, telling you it's missing a texture.
Take care about new textures when working with projects in folder, if you save your job in CAPX after importing a new tile object, all the others will be missing on the CAPX and you can lose your project.