sending information to arduino serial port in python

I'm sending data from an Atom feed from a python script to my Arduino board. I can succesfully communicate with the board the first time, but afterwards, I get a serial exception error from the pySerial module.

Here is my python code:

import serial, sys, feedparser

#Settings
USERNAME = "user"
PASSWORD = "pw"
PROTO = "https://"
SERVER = "gmail.google.com"
PATH = "/gmail/feed/atom"

SERIALPORT = "\\\\.\\COM6"

try:
    ser = serial.Serial(SERIALPORT, 9600)
except serial.SerialException:
    print "failed to write to port %s" % SERIALPORT 
    sys.exit()

newmail = int(feedparser.parse(PROTO + USERNAME + ":" + PASSWORD + "@" + SERVER + PATH)    ["feed"]["fullcount"])
print newmail
ser.write(newmail)

ser.close()

Again, I can send a successful message to my board the first time, but afterwards it fails to the exception.

Here is my code for the Arduino board acting as a pseudo-server.

int led = 13;
int mail = LOW;
int val;

void setup()
{
  pinMode(led, OUTPUT);
  Serial.begin(9600);
  Serial.flush();
}

void loop()
{
  if (Serial.available()>0)
  {
    val=Serial.read();
    Serial.println(val);
    if(val > 0)
      digitalWrite(led, HIGH);
    else
      digitalWrite(led, LOW);
  }
}

Is there something I need to do at the end of the Serial communication in the Arduino board to reset communications? If I physically reset the Arduino board I can again send another write to the board, but not otherwise. Any suggestions?