For the Pro version you have to use the "Pro_Studio_bin" binary version. Run it and should be fine. I have checked on both free and Pro version using Steam Pro and both work fine with no issues. Its something you havent done right. Download latest versions from Ithio again - just refreshed them again now for both the 'Terrain walk sounds' plus the latest API's version 2
Viewing post in CopperCube - Terrain sounds ++ comments
I've fixed the problem! The ccbGetClosestNode had incorrect parameters set in the behavior_Terrain_walkSurface,js script. I commented out the line below and replaced it to make it work with the updated APIV2 function:
// get fall collision node
if (this.using_water && collPos.y < water_height) { collideNode = this.water_node; }
//else {collideNode = ccbGetClosestNode(pos.x, playerY, pos.z, collPos.x, collPos.y-0.5, collPos.z);}
else {collideNode = ccbGetClosestNode(collPos.y);}