Unfortunately the linked crash reports haven't been send or have an [@ EMPTY] signature and do not provide useful crash data that makes it possible to tell something about the cause.

Do you have crash reports with a "bp-" prefix that were submitted and that show a crashing thread?

Try to disable hardware acceleration in Firefox.

• Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

• https://hacks.mozilla.org/2010/09/hardware-acceleration/

See also:

• http://kb.mozillazine.org/Firefox_crashes
• https://support.mozilla.org/kb/Firefox+crashes

At least as of today, all those crashes are correctly logged at crash-stats, and all are [@ EMPTY] signature. For example https://crash-stats.mozilla.com/report/index/bp-fcca6c0b-3683-4ef2-87d8-9f3c42130126

Did crashing start in version 18 only? If it did, then I'd suspect an addon. Does it still crash after cor-el's suggestions, including starting in safe mode?

If it still crashes, you'll need to get a stacktrace using https://developer.mozilla.org/en/How_to_get_a_stacktrace_with_WinDbg