I found an old model of a road from the time of Reloaded and I deposited it on a map of Max. I tried assigning it sound 10 (Tarmac) and it worked. But for several days, I have been unable to get the sound (footsteps) to work on this road.

I recovered all the files, here in a "Road 03.rar" file.

I modified the .fpe (materialindex=10) and it worked for 1 day or 2.
But for several days now it hasn't worked and I don't know why.

Well, ok, it's an old model.
But if I know how to proceed with this one, I would know how to proceed with the others.

Thanks for your help.

[MOD EDIT]
Sorry you cannot post models you did not create yourself.
There are very strict rules that can lead to a ban

Ok I understand. Receive my apologies.
Can I publish the .fpe and the .X , without textures ?

best thing to do is post on github and then if they need the model for specific testing you can email it directly to the team - though it's unlikely they will need it if it's a material index issue