Can't Compile from SVN, undefined reference to `QJson::Parser::~Parser()

Hello,
I'm running Ubuntu 10.10 and am unable to build Kdenlive with rotoscoping enabled.
As I uninstall Qjson, Kdenlive build fine without the rotoscoping tools. But when I try to build it with Qjson installed on my system, make gives me the following error:

CMakeFiles/kdenlive.dir/rotoscoping/rotowidget.o: In function `RotoWidget::getSpline()':
/home/gott/kdenlive/src/rotoscoping/rotowidget.cpp:122: undefined reference to `QJson::Serializer::Serializer()'
/home/gott/kdenlive/src/rotoscoping/rotowidget.cpp:123: undefined reference to `QJson::Serializer::serialize(QVariant const&)'
/home/gott/kdenlive/src/rotoscoping/rotowidget.cpp:123: undefined reference to `QJson::Serializer::~Serializer()'
CMakeFiles/kdenlive.dir/rotoscoping/rotowidget.o: In function `RotoWidget':
/home/gott/kdenlive/src/rotoscoping/rotowidget.cpp:43: undefined reference to `QJson::Parser::Parser()'
/home/gott/kdenlive/src/rotoscoping/rotowidget.cpp:45: undefined reference to `QJson::Parser::parse(QByteArray const&, bool*)'
/home/gott/kdenlive/src/rotoscoping/rotowidget.cpp:66: undefined reference to `QJson::Parser::~Parser()'
/home/gott/kdenlive/src/rotoscoping/rotowidget.cpp:43: undefined reference to `QJson::Parser::Parser()'
/home/gott/kdenlive/src/rotoscoping/rotowidget.cpp:45: undefined reference to `QJson::Parser::parse(QByteArray const&, bool*)'
/home/gott/kdenlive/src/rotoscoping/rotowidget.cpp:66: undefined reference to `QJson::Parser::~Parser()'
collect2: ld returned 1 exit status
make[2]: *** [src/cmake_bindir/kdenlive] Fehler 1
make[1]: *** [src/cmake_bindir/CMakeFiles/kdenlive.dir/all] Fehler 2
make: *** [all] Fehler 2

Have you an idea what's wrong here?

Greetings,
Björn