Jerome,
I strongly suggest that you submit a support request to NI at ni.com/ask. But first, try the following.
The error you are receiving is a missing file. The source could be your build. I have received error 7 on many occasions building an app (on Windows) because I had the source code open. Be sure that you first open all of your code, and do a "Save All". Then, close all code, and close LabVIEW. This will ensure that all VIs are out of memory. Then, open the app builder anew, and try building your application.
If you still have the problem, try doing a test build of a simple "Hello world" type of VI that has no subVI calls. Follow the procedure above to dump the memory, and build it. If you still have the error, then the problem is with
the Application Builder, at which point, you will want to contact NI.