ocl:detectmultiscale error with traincascade

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Hello, I have created training xml files from opencv_haartraining, opencv_traincascades and opencv_traincascade(using HOG). All three of them work when using the CascadeClassifier:detectmultiscale

However, when I use the OclCascadeClassifier:detectmultiscale, only the older haartraining xml works, the other two xml files give me the following error:

OpenCV Error: Null pointer (Invalid classifier cascade) in cv::ocl::OclCascadeClassifier::oclHaarDetectObjects, file C:\builds\2_4_PackSlave-win32-vc11-shared\opencv\modules\ocl\src\haar.cpp, line 686

Why is it not woorking for the newer training files, and why is the cpu version working but not this.

Any ideas are greatly appreciated as I am completely stuck with this