updating word file using php

hi guys!
here is my problem...

I have to append a string "See the solution file" in at the end of almost 3000 MS word (.doc) files.

I am using this

$file="filename.doc";
$fp=fopen($file, "a+");
$cmnt="See the solution file";
fwrite($fp, $cmnt);
fclose($fp);

it works fine if i use

$file="filename.txt"; or $fp=fopen($file,"w+");
txt file(need to update doc) (writing whereas i need to append data)

what to do?
need solution on urgent basis...
thanks in advance

 

<?php
$word = new COM("word.application") or die ("couldnt create an instance of word");
echo "loaded , word version{$word->version}";
//bring word to the front
$word->visible = 1;
//open a word document
$word->Documents->Add();
//add some text to the document
$word->Selection->TypeText("this is some sample text in the document");
//save the document as sampleword.doc
$word->Documents[1]->SaveAs("sampleword.doc");
//close word
$word->Quit();
//free object resources
$word->Release();
$word = null;
?>
--------------------------------------------------------

 

not on a linux server

 

its not working...i need to append data in already existing files... whereas this code is writing text to a new word file, removes previous data and ask to save...it would be hazard to save 3000 files.