NSBundle error for certain projects

I'm migrating all of our projects from WOLips 3.3 to 3.6. Everything is fine
so far, except for two projects. When I try to launch them, I get:

NSBundle: Unable to determine the project type for
'/Users/probert/Workspace/Migration36/ExerciceIllegal/build/ExerciceIllegal.woa/Contents/Resources'.
Guessing it is a framework.

And later, I get:

[2010-12-09 14:29:53 EST] <main> java.lang.IllegalArgumentException: When
'er.javamail.centralize' is true (default), all outgoing mails will get sent
to 'er.javamail.adminEmail' instead of the normal TO addresses, but you did
not provide a valid email for that property.

at er.javamail.ERJavaMail.initializeFrameworkFromSystemProperties(
ERJavaMail.java:132)

And I'm getting this exception even if the proper properties are set. So I
did a couple of checks, and the properties coming from the Properties file
are not read at all. I guess that's because of the NSBundle problem. I tried
to do a clean on the project a couple of times, same error everything.

If I build the project with Ant, the build look like this:

mbp-pascal-robert-2:ExerciceIllegal.woa probert$ ls -l
total 0
drwxr-xr-x   3 probert  admin  102  9 déc 14:40 Contents
drwxr-xr-x  17 probert  admin  578  9 déc 14:40 Frameworks

No startup script and no Resources directories in Contents/,
only WebServerResources is there.

What is wrong?