Broken pdf.php file

[DDD]

Hi,

I was trying to edit my invoice by following the instructions in this thread:
http://www.prestashop.com/forums/viewthread/57538/development/solved_how_to_insert_vat_number_in_pdf_invoice

I missed to do a backup and after the changes pdfs could not be created anymore. I got an error saying something about "already been sent". I tried to change the file back the way it was before but without any luck. Then I tried to download whole prestashop again and upload a new pdf.php file. This didn't work either but I got a different error message. Now it says that there is either a programming error or the page is under update. HTTP 500 - internal server error.

I'm on Prestashop Version 1.2.4.0

What should I do? Please help me!

Best regards

Hans
www.drakfisken.se