Just faced the same issue using Eclipse 4.7.3a (Subversive 4.0.5 - Collaborator 11.0.11000.001).
java.lang.NoClassDefFoundError: Could not initialize class com.smartbear.collaborator.subversive.SVNConnectorSubversionClient$SvnDepth
at com.smartbear.collaborator.subversive.SVNConnectorSubversionClient$2.run(SVNConnectorSubversionClient.java:305)
at com.smartbear.collaborator.subversive.SVNConnectorSubversionClient$2.run(SVNConnectorSubversionClient.java:302)
at com.smartbear.collaborator.subversive.SVNConnectorSubversionClient.run(SVNConnectorSubversionClient.java:672)
at com.smartbear.collaborator.subversive.SVNConnectorSubversionClient.info(SVNConnectorSubversionClient.java:301)
at com.smartbear.collaborator.subversive.SVNConnectorSubversionClient.info(SVNConnectorSubversionClient.java:286)
Which plugin versions are compatible?