Problem with Distance Matrix Hierarchical Clustering

Hi, I’ve just found KNIME recently and I am very happy that it can deal with distance matrices. However I have the following problem: I read in a distance matrix with Distance Matrix Reader but then the Hierarchical Clustering (DistMatrix) does not work: ` Distance matrix column ‘null’ does not exist’. I tried k-medoids, which works fine. Thanks for any help.

Did you choose the right column in the dialog of the hierarchical clustering node?