Checking Email address in notepad from Flash

Hi Guys…

I want help from you guys…

Now im developing one flash site. In that i have one form details… I completed the form using php. when we user register all the data will store in one notepad file. Now i have one more form for referring friends… When users referring his/her friends in that form i have one field his/her (Referral Email id/phone no) text field. Once User submit the form first i want to check if this user already register with us or not. So i want to check the notepad file for his email id / phone no. if he already registered then only form will submit.

So please guys im in very dead end of project completion. How to check email id/ phone no in notepad file from flash?

Please guys help me… Thanks in Advance…