Conkeror fails to start, and an error is dumped to the console.  Happened
to a user with XULRunner 7 on Arch.  Stack trace is as follows:

Error initializing.
NS_ERROR_XPC_GS_RETURNED_FAILURE: Component returned failure code: 0x80570016
(NS_ERROR_XPC_GS_RETURNED_FAILURE) [nsIJSCID.getService]
null()@chrome://conkeror/content/services.js:22
load1()@file:///usr/share/conkeror/components/application.js:102
null()@file:///usr/share/conkeror/components/application.js:177
null()@file:///usr/share/conkeror/components/application.js:278
null()@chrome://conkeror/content/conkeror.js:20
load1()@file:///usr/share/conkeror/components/application.js:102
null()@file:///usr/share/conkeror/components/application.js:177
null()@file:///usr/share/conkeror/components/application.js:278
application()@file:///usr/share/conkeror/components/application.js:35
null()@resource://gre/modules/XPCOMUtils.jsm:301
null()@file:///usr/share/conkeror/components/command-line.js:20
Console error: [JavaScript Error: "conkeror.handle_command_line is not a function" {file:
"file:///usr/share/conkeror/components/command-line.js" line: 23}]
  Category: XPConnect JavaScript