I'll check it gimme a sec I'll edit this post when I do.
EDIT:
It had a few errors in it, so I went ahead and patched it for you:
@name Test
@persist [Players Array]:array
if(first()|duped()){
    runOnChat(1)
   
    Version=0.1
   
    hint("Steam ID Retriever v"+Version,5)
    hint("!scan, to scan players Steam ID and Names",5)
}
findByClass("player")
Players=findToArray()
if(owner():lastSaid():lower()=="!scan")
{
    for(I=1,Players:count())
    {
    Array[I,string] = Players[I,entity]:name() + " || " + Players[I,entity]:steamID()
    }
    for(K=1,Players:count())
    {
        print(Array[1,string])
    }
}
Here's a list of the things that was wrong:
-the hint feature uses hint(S,N) S of course is what it says, the N is how long the hint stays.
-(Array[I,string]=Players[I,entity]:name()+" || "+steamID()) should of been Array[I,string]=Players[I,entity]:name()+" || "+steamID()
-forgot using "{ and }" only once.