Open 6.6, make some kind of change to anything. Try opening 6.7, and you get nothing.

Error:
loading default prefs from: /igb_default_prefs.xml
loading user prefs from: http://www.bioviz.org/igb/releases/current/igb_prefs.xml
loading prefs from url: http://www.bioviz.org/igb/releases/current/igb_prefs.xml
Feb 13, 2012 1:13:46 PM com.affymetrix.igb.stylesheet.XmlStylesheetParser getSystemStylesheet
INFO: Loading system stylesheet from resource:/igb_system_stylesheet.xml
Feb 13, 2012 1:13:46 PM com.affymetrix.igb.prefs.WebLink autoLoad
INFO: Loading web links from file "/Users/auser/.igb/weblinks.xml"
ERROR: Bundle com.affymetrix.igb.IGB [22] EventDispatcher: Error during dispatch. (java.lang.NumberFormatException: For input string: "")
java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
at java.lang.Integer.parseInt(Integer.java:470)
at java.lang.Integer.parseInt(Integer.java:499)
at com.affymetrix.igb.general.ServerList.getServerOrder(ServerList.java:106)
at com.affymetrix.igb.general.ServerList.access$000(ServerList.java:42)
at com.affymetrix.igb.general.ServerList$1.compare(ServerList.java:115)
at com.affymetrix.igb.general.ServerList$1.compare(ServerList.java:112)
at java.util.Arrays.mergeSort(Arrays.java:1270)
at java.util.Arrays.mergeSort(Arrays.java:1281)
at java.util.Arrays.sort(Arrays.java:1210)
at java.util.Collections.sort(Collections.java:159)
at com.affymetrix.igb.general.ServerList.getAllServers(ServerList.java:111)
at com.affymetrix.igb.general.ServerList.getEnabledServers(ServerList.java:70)
at com.affymetrix.igb.general.ServerList.getPrimaryServer(ServerList.java:520)
at com.affymetrix.igb.view.load.GeneralLoadUtils.loadServerMapping(GeneralLoadUtils.java:1027)
at com.affymetrix.igb.view.load.GeneralLoadView.<init>(GeneralLoadView.java:93)
at com.affymetrix.igb.view.load.GeneralLoadView.init(GeneralLoadView.java:81)
at com.affymetrix.igb.view.load.GeneralLoadViewGUI.init(GeneralLoadViewGUI.java:41)
at com.affymetrix.igb.IGB.init(IGB.java:293)
at com.affymetrix.igb.Activator.run(Activator.java:180)
at com.affymetrix.igb.Activator.access$000(Activator.java:45)
at com.affymetrix.igb.Activator$1.addingService(Activator.java:120)
at org.osgi.util.tracker.ServiceTracker$Tracked.customizerAdding(ServiceTracker.java:980)
at org.osgi.util.tracker.ServiceTracker$Tracked.customizerAdding(ServiceTracker.java:906)
at org.osgi.util.tracker.AbstractTracked.trackAdding(AbstractTracked.java:262)
at org.osgi.util.tracker.AbstractTracked.track(AbstractTracked.java:234)
at org.osgi.util.tracker.ServiceTracker$Tracked.serviceChanged(ServiceTracker.java:941)
at org.apache.felix.framework.util.EventDispatcher$4.run(EventDispatcher.java:925)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.felix.framework.util.EventDispatcher.invokeServiceListenerCallback(EventDispatcher.java:921)
at org.apache.felix.framework.util.EventDispatcher.fireEventImmediately(EventDispatcher.java:793)
at org.apache.felix.framework.util.EventDispatcher.fireServiceEvent(EventDispatcher.java:543)
at org.apache.felix.framework.Felix.fireServiceEvent(Felix.java:4252)
at org.apache.felix.framework.Felix.registerService(Felix.java:3275)
at org.apache.felix.framework.BundleContextImpl.registerService(BundleContextImpl.java:346)
at org.apache.felix.framework.BundleContextImpl.registerService(BundleContextImpl.java:320)
at com.affymetrix.igb.window.service.def.Activator.start(Activator.java:61)
at org.apache.felix.framework.util.SecureAction$Actions.run(SecureAction.java:1600)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.felix.framework.util.SecureAction.startActivator(SecureAction.java:632)
at org.apache.felix.framework.Felix.activateBundle(Felix.java:1977)
at org.apache.felix.framework.Felix.startBundle(Felix.java:1895)
at org.apache.felix.framework.Felix.setActiveStartLevel(Felix.java:1191)
at org.apache.felix.framework.FrameworkStartLevelImpl.run(FrameworkStartLevelImpl.java:295)
at java.lang.Thread.run(Thread.java:680)
Feb 13, 2012 1:13:46 PM com.affymetrix.main.OSGiHandler startOSGi
INFO: OSGi is started with org.apache.felix.framework version 4.0.1