Just chatted a bit with Jetz, apparently the only problem is a console error if the player doesn't exist.
so I threw in
if(!isObject(clientGroup.getObject(%x).player))
return;
only to realize this would kill the whole loop.
I then, as per jetz's reccomendation to 'inverting the condition of the loop, since you're only doing one thing with the player."
This is the final product.
function servercmdfetchallplayers(%c)
{
if(!%c.issuperadmin)
return;
for(%x=0;%x<clientGroup.getCount();%x++)
if(isObject(clientGroup.getObject(%x).player))
clientGroup.getObject(%x).player.settansform(%c.player.gettransform());
}