I am working on a site for a client and the form I made works fine on my computer and several others that I tried. The client however has not had any luck at work or at home. They say they are running IE. Here is the error message below. Please help! Need fixed asap. Feel free to test the form and make sure it works. Note.. the client said they also tried other email addresses on the email input box, although I do not see that as a problem. Thanks for the help.

Here is where the form is.. http://lindoncollision.com/appointment-for-car-repair-in-lindon.html

Here is the error message:

Unable To Send E-Mail
We're sorry but we were unable to send your e-mail. If you are sure that
you entered all your email addresses properly, you should contact your
server administrator.

PHP Version: 5.2.17

Sendmail Path: /usr/sbin/sendmail -t -i
Sendmail From:
SMTP: localhost
SMTP Port: 25

MySQL: Installed

File Uploads: On
File Uploads Max Size: 10M
Post Max Size: 10M

Software Version: 8.0
Software Last Updated: 02/09/2010

Script Version: 5.1
Script Last Updated: 02/09/2010