Error when requesting dcat of dataset

[GordianDziwis]

dcat import ckan --host=http://localhost:5000 --dataset=electric-bikesharing-stations > dcat.nt

gives:

2018-11-13 14:42:57,721 [main] INFO  org.aksw.dcat_suite.cli.main.MainCliDcatSuite: Importing dataset electric-bikesharing-stations
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/validator/routines/UrlValidator
	at org.aksw.jena_sparql_api.utils.model.NodeMapperFactory.lambda$static$0(NodeMapperFactory.java:17)
	at org.aksw.jena_sparql_api.utils.model.NodeMapperUriOrString.toNode(NodeMapperUriOrString.java:43)
	at org.aksw.jena_sparql_api.utils.model.NodeMapperUriOrString.toNode(NodeMapperUriOrString.java:17)
	at org.aksw.jena_sparql_api.utils.model.SetFromMappedPropertyValues.add(SetFromMappedPropertyValues.java:33)
	at org.aksw.dcat.jena.domain.api.DcatDistributionCore.replace(DcatDistributionCore.java:49)
	at org.aksw.dcat.jena.domain.api.DcatDistributionCore.setDownloadURL(DcatDistributionCore.java:44)
	at java.util.Optional.ifPresent(Optional.java:159)
	at org.aksw.ckan_deploy.core.DcatCkanRdfUtils.convertToDcat(DcatCkanRdfUtils.java:311)
	at org.aksw.ckan_deploy.core.DcatCkanRdfUtils.convertToDcat(DcatCkanRdfUtils.java:203)
	at org.aksw.ckan_deploy.core.DcatCkanRdfUtils.convertToDcat(DcatCkanRdfUtils.java:191)
	at org.aksw.dcat_suite.cli.main.MainCliDcatSuite.processCkanImport(MainCliDcatSuite.java:424)
	at org.aksw.dcat_suite.cli.main.MainCliDcatSuite.main(MainCliDcatSuite.java:275)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.validator.routines.UrlValidator
	at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 12 more