You need to build up a table with all options in advance. Example:
local soundtable = {
stone = {
"vispath:sounds/steps/stone1.ogg",
"vispath:sounds/steps/stone2.ogg"
,
"vispath:sounds/steps/stone3.ogg"
,
"vispath:sounds/steps/stone4.ogg"
},
wood {
"vispath:sounds/steps/wood1.ogg",
"vispath:sounds/steps/wood2.ogg"
,
"vispath:sounds/steps/wood3.ogg"
,
"vispath:sounds/steps/wood4.ogg"
}
}
local v = getObject("Values[FootstepSound]"):getStr(VValueString)
local r = math.random(1,5)
startSound(soundtable[v][r], {flags=1, volume=20})