Do you know why it is whenever i save a replay (from a parkour mod i downloaded) next time i view it i just run on the air instead of running on the mod building, bench, etc. Also how can i fix this problem. Thanks for your help guys.

You need to get the actual mod. You need to download it then put it in your tb folder*. If you don't know the name of the mod, you can ask the maker of the replay or open the replay up in Notepad.

*where Star said

I saved it to my tb folder -.-
And my version in 3.91, never works though. Its really annoying.

Did you save it to C://Games/Toribash-3.91/data/mods
?

yes i did.

I'd say you should open your replay file with notepad and see if you see the mod name up top but thats just my opinion.