Sending emails to separate accounts using a for loop

For whatever reason, this part:

for ($z = 1; $z <= $Number_of_Categories; $z++)

is the offender. even though $Number_of_Categories was defined above where it is used, the value wasn’t holding. I had to build a function instead, and do this:

function get_Number_of_Categories(){
  return "2";
}

for ($z = 1; $z <= get_Number_of_Categories(); $z++)

once I did that, the loop worked.