field is inaccessible

[stridder]

Hello,
I need help to read the compilation error below:

===============================================
[100%] Building CXX object CMakeFiles/step-22.dir/step-22.cc.o
In file included from /media/sf_Eclipse_Deal_II_sharedFolder/Eclipse_Win_workspace/ChannelFlowWithFlatPlateSource/src/commonIncludeFiles.h:40:0,
from /media/sf_Eclipse_Deal_II_sharedFolder/Eclipse_Win_workspace/ChannelFlowWithFlatPlateSource/src/ChannelFlow.cpp:1,
from /media/sf_Eclipse_Deal_II_sharedFolder/Eclipse_Win_workspace/ChannelFlowWithFlatPlateSource/step-22.cc:12:
/home/ubuntu/deal.II/installed/include/deal.II/fe/fe_values.h: In member function �void ChannelFlow::assemble_system(int, double)’:
/home/ubuntu/deal.II/installed/include/deal.II/fe/fe_values.h:1262:29: error: �std::vector<double> dealii::FEValuesData<2, 2>::JxW_values’ is inaccessible
std::vector<double> JxW_values;
^
In file included from /media/sf_Eclipse_Deal_II_sharedFolder/Eclipse_Win_workspace/ChannelFlowWithFlatPlateSource/step-22.cc:12:0:
/media/sf_Eclipse_Deal_II_sharedFolder/Eclipse_Win_workspace/ChannelFlowWithFlatPlateSource/src/ChannelFlow.cpp:331:22: error: within this context
* fe_values.JxW_values(quadIndex); //divergence-free term (div U, q)
^
/media/sf_Eclipse_Deal_II_sharedFolder/Eclipse_Win_workspace/ChannelFlowWithFlatPlateSource/src/ChannelFlow.cpp:331:42: error: no match for call to �(std::vector<double>) (unsigned int&)’
* fe_values.JxW_values(quadIndex); //divergence-free term (div U, q)
============================= ^
fe_values is defined as

	FEValues<2> fe_values(feSpace, quadrature_formula,
			update_values | update_gradients | update_JxW_values);

fe_values.h and FEValues class comes from a library and can be accessed here:
http://www.dealii.org/8.2.1/doxygen/deal.II/fe_2fe__values_8h_source.html

Thank you.