Problem reproduced on 1.6.0_02-ea-b01:

java version "1.6.0_02-ea"
Java(TM) SE Runtime Environment (build 1.6.0_02-ea-b01)
Java HotSpot(TM) Server VM (build 1.6.0_02-ea-b01, mixed mode)

Here's a test case:

------------- a/A.java -------------
public class A {
    private B b;
    public void aMethod() {
        b.doSomething(true);
    }
}
------------------------------------


------------- b/B.java -------------
public class B {
    public void doSomething(boolean b) {
    }
    public void doSomething(C c) {
    }
}
------------------------------------



------------- c/C.java -------------
public class C {
}
------------------------------------



----------- ./compile.sh -----------
java -version
rm -rf c/C.class
rm -rf b/B.class
rm -rf a/A.class

javac c/C.java
javac b/B.java -cp c/
javac a/A.java -cp b/
------------------------------------



The output is:

a/A.java:5: cannot access C
class file for C not found
        b.doSomething(true);
         ^
1 error

(Note: B.java and C.java have compiled)