The method in the function below, for adding file attachments to an email, works on a windows based web server but not on a linux based web server.

function AddInvFileData($FromEmail, &$EmailBody, &$EmailHeader)
{
global $strInvFileName;
$fileInv = fopen($strInvFileName, "rb");
$nRandNum = 0;
$strMIMEBoundary = "";
$strMessage = "";
$bResult = false;

if ($fileInv)
{
$bResult = true;

// Read the file contents.
$InvFileData = fread($fileInv, filesize($strInvFileName));
fclose($fileInv);

//Encode it for email - "\r\n" every 76 charcters.
$InvFileData = chunk_split(base64_encode($InvFileData));

# Get a random 32 bit number using time() as seed.
$nRandNum = md5(time());

# Define the main headers.
$EmailHeader = "From:".$FromEmail."\r\n";
$strMIMEBoundary = "==Multipart_Boundary_x{".$nRandNum."}x";

$EmailHeader .= "\nMIME-Version: 1.0\nContent-Type: multipart/mixed;\n boundary=\"{".$strMIMEBoundary."}\"";

# Define the message section
$strMessage = "This is a multi-part message in MIME format.\n\n" .
"--{".$strMIMEBoundary."}\nContent-Type: text/plain; charset=\"iso-8859-1\"\n" . "Content-Transfer-Encoding: 7bit\n\n".$EmailBody."\n\n";


# Define the attachment section
$strMessage .= "--{".$strMIMEBoundary."}\nContent-Type: {TEXT};\n".
" name=\"{Invoice}\"\nContent-Disposition: attachment;\n".
filename=\"Invoice.txt\"\nContent-Transfer-Encoding: base64\n\n".
$InvFileData."\n\n--{".$strMIMEBoundary."}--\n";
$EmailBody = $strMessage;
}
return $bResult;
}

It results in the following contents when the email is sent to my PC. How do you get this to work properly on a linux web server, i.e. such that the file attachment can be opened and saved in Microsoft Outlook etc.

MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="{==Multipart_Boundary_x{2657b10f00b9ee73 7cbb6ee86912cdc0}x}"

This is a multi-part message in MIME format.

--{==Multipart_Boundary_x{2657b10f00b9ee737cbb6ee869 12cdc0}x}
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

Billing details
--------------------
Sally Wheeler

Email:
Phone:
Mobile:

Delivery details
--------------------


Email:
Phone:
Mobile:

Paying via: Deposit

Additional instructions
------------------------

Please could I use PayPal?

Items
------
LS014 Olearia lirata Tube $3.50 1 $3.50
SS013 Dillwynia phylicoides Tube $3.50 1 $3.50
SS014 Dillwynia sericea Tube $3.50 1 $3.50
CL003 Glycine clandestina Tube $3.50 1 $3.50
SP001 Brachyscome basaltica Tube $3.50 1 $3.50
Postage: $13.00 ($10.55)
--------
Grand Total: $30.50


--{==Multipart_Boundary_x{2657b10f00b9ee737cbb6ee869 12cdc0}x}
Content-Type: {TEXT};
name="{Invoice}"
Content-Disposition: attachment;
filename="Invoice.txt"
Content-Transfer-Encoding: base64

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--{==Multipart_Boundary_x{2657b10f00b9ee737cbb6ee869 12cdc0}x}--