Javascript Bar Chart not working after first execution anymore

Hy!

I have two Javascript Bar Chart nodes, which work well in the first execution.

After this, in the next run both stop at 40% progress (Generating Image) and do not work any more.

I have to Stop KNIME and kill the remaining process in the task manager.

Then I restart KNIME and it is possible to run the workflow again, for one time.

This does not happen if a do not create the image, but I need the image in a report.

I use KNIME 4.5.1

What should I do?