Please Help! Create account not working!

We set up an online store: https://www.titanammo.com/store

for our clients. The 'create account' function isn't working. When it gets to the part where you fill in the info to create your new account, and then submit it, it displays a 'can't find' html.

The other day I went into the create_account.php to try and change the message that is displayed when you create an account. Could that have broken the site somehow?

I took backed up php files in an attempt to try and restore the function just now, but it doesn't seem to have worked. It's a matter of serious concern to our clients, and I don't have the programming know-how to try and fix it. Is there any way to restore the create-account functionality to our zencart store without having to totally uninstall/reinstall? The changes made to the create_account.php weren't very drastic - I can't imagine that it would totally break the site and require such drastic action. If there's a way to just restore it to the way it was, please let us know.

I tried creating an acount and was presented with a "Blank Page" upon submitting

http://www.zen-cart.com/content.php?124-i-am-getting-a-blank-page-%28or-blank-part-of-a-page%29

Did following the items on this list fix it for you? All I see is a blank page as well. I've tried restoring the backed-up php 'create account' file from when it was working, and that didn't fix it. Do you need to do something else to restore it?

I went into the log file from the FTP. The error log did indeed point to the errant line of code. Thanks for pointing me there - it's fixed now, and that tip was a life-saver!