Declaring a variable to be "extern" inside a namespace causes Shiboken to generate invalid code. I have attached a patch file to recreate the problem using the libsample test case from the Shiboken source code. To summarize:

// In header file
namespace SampleNamespace
{
//...
extern int ExternInt;
}

// In implementation file
namespace SampleNamespace
{
//...
int ExternInt = 0;
}

This causes shiboken to produce invalid code like the following:

static PyObject* Sbk_SampleNamespace_get_ExternInt(PyObject* self, void*)
{
    ::SampleNamespace* cppSelf = 0;
//...

which causes gcc 4.6.2 to complain like so

In function ‘PyObject* Sbk_SampleNamespace_get_ExternInt(PyObject*, void*)’:
error: expected primary-expression before ‘*’ token
error: ‘cppSelf’ was not declared in this scope
error: expected primary-expression before ‘;’ token

A workaround is to add a rejection tag to the typesystem

<namespace-type name="SampleNamespace">
    <!-- ... -->
    <rejection class="*" field-name="ExternInt" />
</namespace-type>