Error when using Convolutional Layer: Message: New shape length doesn't match original length

Hi,

I am trying to setup a simple Deep Learning process using the Deep Learning extension and the MNIST dataset as CSVs of grey values from Kaggle. If I just use two fully connected layers inside the Deep Learning operator everything works, but as soon as I add a convolutional layer and a pooling layer, the apply model steps fails with an error message:

Exception: org.nd4j.linalg.exception.ND4JIllegalStateException
Message: New shape length doesn't match original length: [0] vs [6584816]. Original shape: [8399, 784] New Shape: [33601, 0, 784]

The test dataset is the result of a split operator which is used to have 80% (33601 records)  of the data as training data and 20% (8399 records) as test data.

What am I doing wrong? Any help is highly appreciated

Friedemann