Problem with revisiting the Signup page when capcha is enabled

2007-03-05 16:59:44,935 http-8080-Processor2 ERROR [] [[Standalone].[localhost].[/jira].[captcha]] Servlet.service() for servlet captcha threw exception
java.lang.ClassCastException
	at net.sf.ehcache.Element.equals(Element.java:236)
	at java.util.HashMap.eq(HashMap.java:274)
	at java.util.HashMap.removeEntryForKey(HashMap.java:545)
	at java.util.HashMap.remove(HashMap.java:527)
	at net.sf.ehcache.store.MemoryStore.remove(MemoryStore.java:173)
	at net.sf.ehcache.Cache.remove(Cache.java:999)
	at net.sf.ehcache.Cache.remove(Cache.java:938)
	at net.sf.ehcache.Cache.remove(Cache.java:898)
	at net.sf.ehcache.Cache.remove(Cache.java:880)
	at com.octo.captcha.service.EhcacheManageableCaptchaService.generateAndStoreCaptcha(EhcacheManageableCaptchaService.java:826)
	at com.octo.captcha.service.AbstractCaptchaService.getChallengeForID(AbstractCaptchaService.java:538)
	at com.octo.captcha.service.image.EhcacheManageableImageCaptchaService.getImageChallengeForID(EhcacheManageableImageCaptchaService.java:505)
	at com.atlassian.jira.servlet.CaptchaServlet.doGet(CaptchaServlet.java:31)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at com.atlassian.jira.web.filters.AccessLogFilter.doFilter(AccessLogFilter.java:67)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:182)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at com.atlassian.seraph.filter.LoginFilter.doFilter(LoginFilter.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at com.atlassian.jira.web.filters.ActionCleanupDelayFilter.doFilter(ActionCleanupDelayFilter.java:41)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at com.atlassian.jira.web.filters.RequestCleanupFilter.doFilter(RequestCleanupFilter.java:49)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at com.atlassian.core.filters.AbstractEncodingFilter.doFilter(AbstractEncodingFilter.java:37)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at com.atlassian.jira.appconsistency.db.DatabaseCompatibilityEnforcerFilter.doFilter(DatabaseCompatibilityEnforcerFilter.java:39)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
	at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
	at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
	at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
	at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
	at java.lang.Thread.run(Thread.java:534)