Hey man, thanks for playing. The interaction issue has finally been sorted out with the 4th patch, I couldn't find the issue but now it's fixed.
The fatal error is to do with the plugin I'm using for footsteps, it has a bug. There's nothing I can do about it, unfortunately. The good news is, it happens very rarely. The bad news is you were unlucky haha.
About the sprint, it's not supposed to be "working" from the start, as it's an intended mechanic, but I've added a hidden "speedrun" button in the options that toggles sprint on. Just in case you guys want it.
Thanks again for playing, man.
God bless.