Does that mean that you had another version of KNIME Image Processing before, e.g. from the "KNIME Community Contributions (3.3)" (
trusted/3.3), or from the "nightly builds" update site?
Could it be that you have some version skew now?
It would be helpful if you can report the versions of the different KNIME Image Processing modules in your installation as reported by Help > Installed Software, also possibly also the exact error from your
.metadata/knime/ in your workspace).
I'm sure that @dietzc or @gab1one will be able to advise then.
As a workaround, you can try to make a new KNIME installation and point it to the same workspace.