The template "crashsig" does not exist or has no approved revision. GraphWalker::DoWalk(nsDeque&)
Mozilla developers are aware that this is a common Firefox crash and are working on a fix. If you want to help, you can provide more information on the bug report.
The general crash troubleshooting steps have steps that help with this crash. You can also try providing a few crash IDs when you ask a question in case there is useful information in the crash report that isn't in the crash signature.