Unable to remove filters and dashboards from favorites with Opera

When clicking on the star (meaning favorite) in dashboard/filter management page an error message "Error occurred communicating with the server. Please reload the page and try again" and nothing is done (see screenshots). When clicking OK I get "HTTP Status 415: The server refused this request because the request entity is in a format not supported by the requested resource for the requested method ()."

This problem can be reproduced on jira.atlassian.com with Opera 10.

It seems to work ok with latest Firefox, Chrome and IE browsers though.

From our server logs (Jira 4.1.2 on standalone Tomcat) I can see this error in catalina.out:
It produces an error in the server quite deep in the core libraries:
Nov 17, 2010 7:15:34 PM com.sun.jersey.server.impl.application.WebApplicationImpl onException
SEVERE: Internal server error
javax.ws.rs.WebApplicationException
at com.sun.jersey.server.impl.uri.rules.TerminatingRule.accept(TerminatingRule.java:55)
at com.sun.jersey.server.impl.uri.rules.SubLocatorRule.accept(SubLocatorRule.java:105)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:111)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:71)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:111)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:63)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:654)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:612)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:603)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:309)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:425)
at com.atlassian.plugins.rest.module.RestDelegatingServletFilter$JerseyOsgiServletContainer.doFilter(RestDelegatingServletFilter.java:198)
at com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:689)
at com.atlassian.plugins.rest.module.RestDelegatingServletFilter.doFilter(RestDelegatingServletFilter.java:112)
at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:55)
at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:41)
at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
at com.atlassian.plugins.rest.module.servlet.RestServletUtilsUpdaterFilter.doFilterInternal(RestServletUtilsUpdaterFilter.java:26)
at com.atlassian.plugins.rest.module.servlet.RestServletUtilsUpdaterFilter.doFilter(RestServletUtilsUpdaterFilter.java:40)
at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:55)
at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:41)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.atlassian.jira.web.filters.accesslog.AccessLogFilter.executeRequest(AccessLogFilter.java:99)
at com.atlassian.jira.web.filters.accesslog.AccessLogFilter.doFilter(AccessLogFilter.java:83)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.atlassian.jira.security.xsrf.XsrfTokenAdditionRequestFilter.doFilter(XsrfTokenAdditionRequestFilter.java:50)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:55)
at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:41)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:219)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.atlassian.security.auth.trustedapps.filter.TrustedApplicationsFilter.doFilter(TrustedApplicationsFilter.java:98)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
...