for i=0 to 5 step 1
You wouldn't put quotation marks in there or else you're creating a string.
But what is m.bground.translation? Is it already an array with two elements that you simply want to redefine here?
<blah deblah='7' translation="[0, 0]"/>
In your example, the For loop is pointless, since it will just run six times. You might as well simply set
since that's all you end up with anyway. So I suspect what you have going on and what you really want to do is not set up right way.