Some .gif throw array out of bound exception

30.10.2008 16:18:03 ERROR [org.apache.wicket.RequestCycle.logRuntimeException():1432] Method onFormSubmitted of interface org.apache.wicket.markup.html.form.IFormSubmitListener targeted at component [MarkupContainer [Component id = form, page = org.hippoecm.frontend.plugins.gallery.upload.UploadDialog, path = 13:wizard:form.Form, isVisible = true, isVersioned = false]] threw an exception
org.apache.wicket.WicketRuntimeException: Method onFormSubmitted of interface org.apache.wicket.markup.html.form.IFormSubmitListener targeted at component [MarkupContainer [Component id = form, page = org.hippoecm.frontend.plugins.gallery.upload.UploadDialog, path = 13:wizard:form.Form, isVisible = true, isVersioned = false]] threw an exception
at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:194)
at org.apache.wicket.request.target.component.listener.ListenerInterfaceRequestTarget.processEvents(ListenerInterfaceRequestTarget.java:73)
at org.apache.wicket.request.AbstractRequestCycleProcessor.processEvents(AbstractRequestCycleProcessor.java:91)
at org.apache.wicket.RequestCycle.processEventsAndRespond(RequestCycle.java:1171)
at org.apache.wicket.RequestCycle.step(RequestCycle.java:1248)
at org.apache.wicket.RequestCycle.steps(RequestCycle.java:1349)
at org.apache.wicket.RequestCycle.request(RequestCycle.java:493)
at org.apache.wicket.protocol.http.WicketFilter.doGet(WicketFilter.java:387)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:199)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1065)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:365)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:185)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:689)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:391)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:146)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
at org.mortbay.jetty.Server.handle(Server.java:285)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:457)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:765)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:628)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:209)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:357)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:329)
at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:475)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:183)
... 25 more
Caused by: java.lang.ArrayIndexOutOfBoundsException: -7
at org.hippoecm.frontend.plugins.gallery.gif.GIFEncoder.output(GIFEncoder.java:405)
at org.hippoecm.frontend.plugins.gallery.gif.GIFEncoder.compress(GIFEncoder.java:345)
at org.hippoecm.frontend.plugins.gallery.gif.GIFEncoder.encode(GIFEncoder.java:178)
at org.hippoecm.frontend.plugins.gallery.gif.GIFImageWriter.write(GIFImageWriter.java:62)
at javax.imageio.ImageWriter.write(ImageWriter.java:598)
at org.hippoecm.frontend.plugins.gallery.ImageUtils.createThumbnail(ImageUtils.java:128)
at org.hippoecm.frontend.plugins.gallery.upload.UploadForm.makeThumbnail(UploadForm.java:182)
at org.hippoecm.frontend.plugins.gallery.upload.UploadForm.onSubmit(UploadForm.java:154)
at org.apache.wicket.markup.html.form.Form$12.component(Form.java:1365)
at org.apache.wicket.MarkupContainer.visitChildren(MarkupContainer.java:829)
at org.apache.wicket.MarkupContainer.visitChildren(MarkupContainer.java:844)
at org.apache.wicket.markup.html.form.Form.delegateSubmit(Form.java:1358)
at org.apache.wicket.markup.html.form.Form.onFormSubmitted(Form.java:810)