It appears that the code is not compatible with 1.4, as the method doesn't exist on String.

java.lang.NoSuchMethodError: java.lang.String.contains(Ljava/lang/CharSequence;)Z
at com.atlassian.bamboo.setup.johnson.BambooJohnsonSetupConfig.isSetupPage(BambooJohnsonSetupConfig.java:27)
at com.atlassian.johnson.filters.JohnsonFilter.doFilter(JohnsonFilter.java:83)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:823)
at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:83)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:823)
at com.atlassian.seraph.filter.LoginFilter.doFilter(LoginFilter.java:91)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:823)
at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:473)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:567)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1565)
at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:635)
at org.mortbay.http.HttpContext.handle(HttpContext.java:1517)
at org.mortbay.jetty.plus.PlusWebAppContext.handle(PlusWebAppContext.java:158)
at org.mortbay.http.HttpServer.service(HttpServer.java:954)
at org.mortbay.http.HttpConnection.service(HttpConnection.java:814)
at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:981)
at org.mortbay.http.HttpConnection.handle(HttpConnection.java:831)
at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:244)
at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)