Why i cannot use if and else here?

PHP
i wonder how i can use if and else statement in the code below
if i use if-else in code below i received an error message


$data1 = $data1 = "$datas | {$this->arrayAddressReturn_value[$i]} | $this->GetFileNameReturn"


if ($StudentPull == 0)  {//get file from config.php
switch($this->GetstudentID[$i])  //to get student id from other function
{
  case 1: $fn = $file1; break;
  case 2: $fn = $file2; break;
}

file_put_contents('c:\\'.$fn.'.txt',$data1 , FILE_APPEND);
}
}

else
{
foreach($this->GetFileNameReturn as $FileName) //get file from database
      {
 switch($this->GetstudentID[$i])
{
  case 1: $fn = $FileName; break;
  case 2: $fn = $FileName; break;
  case 3: $fn = $FileName; break;
// default:$fn = UNKNOWN; break;
}

file_put_contents('c:\\'.$fn.'.txt',$data1 , FILE_APPEND);
      }
}
}