exception preventing launch after downgrade

I am trying to downgrade from Marvin 16.8.1 back to Marvin 16.4.25, but I am getting a Java runtime exception that causes the launch process to hang at the Applet is loading... Please wait... stage. The Java console says:

JMSketch initalization has failed.

java.lang.NoClassDefFoundError: chemaxon/marvin/modules/datatransfer/rtf/DocumentConversionException

	at chemaxon.marvin.applet.JMSketch.createGUI(Unknown Source)

	at chemaxon.marvin.applet.AbstractMarvinApplet.init(Unknown Source)

	at chemaxon.marvin.applet.JMSketchLaunch.showApplet(Unknown Source)

	at chemaxon.marvin.applet.AppletLaunch$3.run(Unknown Source)

	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:301)

	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)

	at java.awt.EventQueue.access$500(EventQueue.java:97)

	at java.awt.EventQueue$3.run(EventQueue.java:709)

	at java.awt.EventQueue$3.run(EventQueue.java:703)

	at java.security.AccessController.doPrivileged(Native Method)

	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)

	at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)

	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)

	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)

	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)

	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)

	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)

	at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Caused by: java.lang.ClassNotFoundException: chemaxon.marvin.modules.datatransfer.rtf.DocumentConversionException

	at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)

	at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Unknown Source)

	at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)

	at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)

	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

	... 18 more

What could be causing this problem? I have repeatedly emptied both the browser and Java caches. This problem only occurred after I tried to downgrade from Marvin 16.8.1 back to Marvin 16.4.25. If I go ahead and switch to Marvin 16.8.1, everyting works fine. At first I thought the problem might be in my configuration files, but I think I've ruled out that possibility now. I have tried the launch with a few different structures to load; no joy with any of them.

Hi Bob,

The issue is the same as you discovered here. The following version of Marvin which is 16.5.2.0 contains the corresponding fix.

Regards, Zoltan.

Alas, that doesn't help me. I need a working version (one that will load, not hang) before Marvin 16.5.2, when the MRArrow was introduced. In that post you reference, I see that Marvin 16.2.29 worked. I suppose that will do for now.