Checking core structure...
compile_project:10: no matches found: *.in
rm -f po-grt-core.jar `find . -name \*.class`
(cd src; javac -encoding UTF-8 `find . -name \*.java`)
./grt/GrtManager.java:14: package pt.utl.ist.po.ui does not exist
import pt.utl.ist.po.ui.InvalidOperation;
                       ^
./grt/GrtManager.java:60: cannot find symbol
symbol  : class InvalidOperation
location: class grt.GrtManager
    public boolean readFile(String filename) throws InvalidOperation {
                                                    ^
./grt/GrtManager.java:111: cannot find symbol
symbol  : class InvalidOperation
location: class grt.GrtManager
    public boolean saveFile(String filename) throws InvalidOperation {
                                                    ^
./grt/GrtManager.java:83: cannot find symbol
symbol  : class InvalidOperation
location: class grt.GrtManager
                            throw new InvalidOperation("Ficheiro com telemóvel de amigo inexistente!");
                                      ^
./grt/GrtManager.java:100: cannot find symbol
symbol  : class InvalidOperation
location: class grt.GrtManager
            throw new InvalidOperation(ex.getMessage());
                      ^
./grt/GrtManager.java:157: cannot find symbol
symbol  : class InvalidOperation
location: class grt.GrtManager
            throw new InvalidOperation(ex.getMessage());
                      ^
6 errors
make: *** [all] Error 1