I figured out how to do it, and decided to post it here just in case someone else was having a similar problem. Instead of using objects, I used arrays by using $row = mysql_fetch_arrays($result,ASSOC)
Then I imploded the $row array and placed it as the value for the checkbox. In the next page this information was posted as an array of imploded arrays. To extract the data I looped through the array exploding each element and storing it in an array, and then immediately processing the array because it would be overwritten with the next iteration of the for loop.
Here is the code for extracting data from an array of imploded arrays:
for ($x=0; $x < sizeof($blah); $x++)
{
$narray = explode("," , $invoice[$x]);
//Do something with $narray because each time the loop iterates the data is overwritten.
}
Or you could just do this:
$array0 = explode("," , $invoice[0]);
$array1 = explode("," , $invoice[1]);
etc.
etc.