Exception when trying to view excel report

Happens when clicking on the excel view in the issue navigator

ERROR [2002-05-02 13:57:24,568] servlet.ExcelIssueNavigatorServlet "Exception: java.lang.NullPointerException"
java.lang.NullPointerException
at com.atlassian.jira.web.servlet.ExcelIssueNavigatorServlet.doGet(ExcelIssueNavigatorServlet.java:84)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:244)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:336)
at com.evermind._ie.doFilter(.:59)
at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:124)
at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:68)
at com.evermind._ic.doFilter(.:16)
at com.atlassian.jira.web.security.SecurityFilter.doFilter(SecurityFilter.java:201)
at com.evermind._ic.doFilter(.:20)
at com.atlassian.jira.web.security.LoginFilter.doFilter(LoginFilter.java:189)
at com.evermind._deb._lnc(.:376)
at com.evermind._deb._wmb(.:170)
at com.evermind._co._wbb(.:581)
at com.evermind._co._fs(.:189)
at com.evermind._bt.run(.:62)