Full-featured Workflow Engine and Standardisation Framework for IBM Lotus Notes
It appears that there is a bad file in the project for the current version of the project. The zip files report damaged header and will not unzip correctly.
Thomas, sounds like you're using Windows built in zip file management? It's buggy. If so, install a proper zip managment tool like Winzip or 7Zip (open source) http://www.7-zip.org/