Sorry to see you're having problems with our mod!

The issue you're experience is due to an update we rolled out a few days ago, you can fix it by following these steps:

1) Open the console. (by default this is done with the ` (tilde) key)
2) Look at the top right of your screen, the name of the map should be there. For example: sp_a1_tramride
3) Type in the console: 'changelevel yourmapname' without the quotation marks eg: 'changelevel sp_a1_tramride'
4) Press Enter
5) The level restarts, and the errors are gone!

We've also made a little youtube tutorial on how to do it if you prefer that:
https://www.youtube.com/watch?v=tBW8F-PURYk