Internal server error - Stack Trace: java.lang.NoSuchMethodError: org.apache.commons.lang.ArrayUtils.add([Ljava/lang/Object;Ljava/lang/Object;)[Ljava/lang/Object;

I'm trying to setup bamboo and the first page throws the following exception

Internal server error
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Version: 0.5.2
Build: 102
Build Date: Oct 13, 2006

Stack Trace: java.lang.NoSuchMethodError: org.apache.commons.lang.ArrayUtils.add([Ljava/lang/Object;Ljava/lang/Object[Ljava/lang/Object;
at com.atlassian.bamboo.user.AcegiBambooUser.getAuthorities(AcegiBambooUser.java:43)
at com.atlassian.bamboo.filter.SeraphLoginFilter.doFilter(SeraphLoginFilter.java:51)
at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:274)
at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:191)
at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:274)
at org.acegisecurity.util.FilterChainProxy.doFilter(FilterChainProxy.java:148)
at org.acegisecurity.util.FilterToBeanProxy.doFilter(FilterToBeanProxy.java:90)
at com.atlassian.bamboo.filter.BambooAcegiProxyFilter.doFilter(BambooAcegiProxyFilter.java:25)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:813)
at com.atlassian.bamboo.filter.LicenseFilter.doFilter(LicenseFilter.java:71)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:813)
at com.atlassian.johnson.filters.JohnsonFilter.doFilter(JohnsonFilter.java:91)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:813)
at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:182)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:813)
at com.atlassian.seraph.filter.LoginFilter.doFilter(LoginFilter.java:177)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:813)
at org.springframework.orm.hibernate.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:174)
at com.atlassian.spring.filter.FlushingSpringSessionInViewFilter.doFilterInternal(FlushingSpringSessionInViewFilter.java:29)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:77)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:813)
at com.atlassian.bamboo.filter.CompressingFilter.doFilter(CompressingFilter.java:69)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:813)
at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:494)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:569)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1482)
at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:624)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1434)
at org.mortbay.jetty.plus.PlusWebAppContext.handle(PlusWebAppContext.java:158)
at org.mortbay.http.HttpServer.service(HttpServer.java:896)
at org.mortbay.http.HttpConnection.service(HttpConnection.java:814)
at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:981)
at org.mortbay.http.HttpConnection.handle(HttpConnection.java:831)
at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:244)
at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:366)
at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)