CGI, PHP Issues for contact form

[#1]

Hi Guys,
I updated my website today, using my usual software, CoffeeCup.  Up until today, my contact form was working perfectly fine.
Now, whenever i try to submit the contact form, my browser attempts to open/save the PHP file.  The link is http://www.thecompleteparty.co.uk/Contact.html
I have been looking through a lot of posts but can't find much which resembles my PHP file.  The file details are below;
<?xml version="1.0" encoding="UTF-8"?>
<form url="myform.php"
window="_self"
method="POST"
fontname="MS Sans Serif"
width="450"
height="368"
bkcolor="0xFFFFFF"
outlinecolor="0x333333"
fontcolor="0x000000"
themecolor="0xFFFF99"
fontcolor2="#000000"
bkcolor2="#FFFFFF"
includeresults="false"
emailuser="false"
reqmessage=""
autoresponse="Thank You for Your Request.  The Complete Party">

<hidden
name="mailto"
value="fun@thecompleteparty.co.uk"
></hidden>
<hidden
name="subject"
value="Webform Request"
></hidden>
<image
image="monitor-1.jpg"
x="29"
y="52"
></image>
<textinput
name="Name"
x="260"
y="48"
w="175"
h="22"
initvalue=""
bkcolor="0xFFFFFF"
  fontname="Arial"
  fontcolor="0x000000"
required="true"
>
</textinput>
<label
name="My Text 1"
x="128"
y="44"
w="54"
h="19"
text="Name:"
fontbold="bold"
  fontname="Arial"
  fontcolor="0xFF00FF"
  fontsize="16"
></label>
<label
name="My Text 2"
x="128"
y="78"
w="56"
h="19"
text="E-Mail:"
fontbold="bold"
  fontname="Arial"
  fontcolor="0xFF00FF"
  fontsize="16"
></label>
<textinput
name="E-Mail Address"
x="260"
y="80"
w="175"
h="22"
initvalue=""
bkcolor="0xFFFFFF"
  fontname="Arial"
  fontcolor="0x000000"
required="true"
emailbox="true"
>
</textinput>
<label
name="My Text 3"
x="128"
y="110"
w="125"
h="19"
text="Phone Number:"
fontbold="bold"
  fontname="Arial"
  fontcolor="0xFF00FF"
  fontsize="16"
></label>
<label
name="My Text 4"
x="16"
y="176"
w="93"
h="19"
text="Comments:"
fontbold="bold"
  fontname="Arial"
  fontcolor="0xFF00FF"
  fontsize="16"
></label>
<textarea
name="Comments"
x="16"
y="204"
w="416"
h="127"
initvalue=""
wordwrap="true"
required="true"
bkcolor="0xFFFFFF"
  fontsize="12"
  fontname="Arial"
  fontcolor="0x000000"
></textarea>
<submitbutton
name="submitbutton1"
x="336"
y="336"
w="100"
h="20"
label="Send"
fontname="Arial"
fontcolor="0x000000"
  fontsize="12"
></submitbutton>
<label
name="My Text 5"
x="68"
y="4"
w="336"
h="22"
text="Contact Us - Fill Out the Form Below"
fontbold="bold"
  fontname="Arial"
  fontcolor="0xFF00FF"
  fontsize="19"
></label>
<label
name="My Text 6"
x="128"
y="140"
w="90"
h="19"
text="Post Code:"
fontbold="bold"
  fontname="Arial"
  fontcolor="0xFF00FF"
  fontsize="16"
></label>
<textinput
name="Phone Number"
x="260"
y="112"
w="175"
h="22"
initvalue=""
bkcolor="0xFFFFFF"
  fontname="Arial"
  fontcolor="0x000000"
required="true"
>
</textinput>
<textinput
name="Post Code"
x="260"
y="144"
w="175"
h="22"
initvalue=""
bkcolor="0xFFFFFF"
  fontname="Arial"
  fontcolor="0x000000"
required="true"
>
</textinput>
</form>

[#2]

Not to worry.....i just went back to my older backup site........it can wait till next week

[#3]

I was in the middle of trying to look at this when you removed it!
Can you confirm that you uploaded the php file to cshell.plus.net (not ftp.plus.net) and that the link to the php file was a full URL beginning http://ccgi...