customized checkout, issue with send email

[ryanb4614]

Hello,
I recently customized my checkout on my store. Ever since I did this, every new customer with an order, when i go to send them an email it says: Notice: FAILED to send Email to all recipients: this is when i click send button. I can successfully email customers that I had before I customized the checkout. Any ideas what it can be? What files can I look at that would be causing this issue. Thank you!

[Kim]

Exactly what did you do to "customize" the checkout?

[ryanb4614]

mostly rearranged the layout, and changed headings and color... feel free to take a look, make a fonny name so i know to remove it p e t l a-n-d p l-u-s .com no spaces or hyphens

[ryanb4614]

The mod I used was:
Order Steps - Tableless <Edited the files in there
also, some how my create_account.php was removed so I uploaded the create_account.php from my backup file from 2-14-09

[ryanb4614]

[UPDATE] I have tried the debugger on the admin side and on the includes side, its not finding it. I am able to update the users order status and that does go through. The ty tracker mod also works, emailing the customer the tracking number, its just in the admin ->send email-> select customer-> preview->send mail and admin->customers->click on customer->send mail-> ect both FAIL. What can this be?

[beyre]

What "debugger" in the Admin ?