Its an array initialization problem... once I sized it correctly when dimensioning the array variable it worked fine:var arrayToStore = [['','',''],['','',''],['','','']]
I had worked that code up in a fiddle and was getting the same error, hence why I posted it with ['','']. The general consensus seems to be to create a helper fuction that, given a number x, can push x number of blank objects into the array which you can then fill.
Or... just use an object. It's certainly the preferred way in JS unless you really need an array of arrays.
# CORRECT WAY TO INSTANTIATE AN ARRAY WITHOUT DIMENSION
var arrayToStore = ;
var arrayToStore = [['',''],['','']];
IF you instantiate the array with only the above "problem" dimensions and do not correct the length beyond this, they will be truncated.
If you do arrayToStore =  and then try to set arrayToStore = something, you'll get the same error.