I just checked mine - I've never used walking mode. It appears that there's a problem with Maps. (I get the "Maps has stopped" message too, but it works fine for driving.)
The odds that we're both running the same app that's causing the problem are slim to none - I'm a developer (not on Android), so I probably have a completely different set of apps than you do. Safe Mode too, so it's most likely just a bug in Maps.