NumberFormatException When Cancelling Page Edits

2012-10-22 22:21:23,956 ERROR [http-8043-6] [atlassian.confluence.servlet.ConfluenceServletDispatcher] sendError Could not execute action
 -- url: /pages/doeditpage.action | userName: admin | referer: http://localhost:8043/pages/editpage.action?pageId=4064
java.lang.NumberFormatException: null
    at java.lang.Long.parseLong(Long.java:375)
    at java.lang.Long.parseLong(Long.java:468)
    at com.atlassian.confluence.pages.Draft.getPageIdAsLong(Draft.java:83)
    at com.atlassian.confluence.pages.actions.AbstractCreateAndEditPageAction.getCancelResult(AbstractCreateAndEditPageAction.java:630)
    at com.atlassian.confluence.pages.actions.AbstractEditPageAction.getCancelResult(AbstractEditPageAction.java:296)
    at com.atlassian.confluence.core.CancellingInterceptor.intercept(CancellingInterceptor.java:20)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
    at com.atlassian.confluence.xwork.HttpMethodValidationInterceptor.intercept(HttpMethodValidationInterceptor.java:72)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
    at com.atlassian.confluence.security.websudo.WebSudoInterceptor.intercept(WebSudoInterceptor.java:63)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
    at com.atlassian.confluence.themes.ThemeContextInterceptor.intercept(ThemeContextInterceptor.java:68)
.....