purchase button hide after logging out wordpress

my purchase button not available when i loged out. but its working good when i logged in wordpress.

### Begin System Info ###

## Please include this information when posting support requests ##

Multisite: No

SITE_URL: http://pg18plus.com/buy
HOME_URL: http://pg18plus.com/buy

EDD Version: 1.7.2
Upgraded From: None
WordPress Version: 3.6.1
Permalink Structure: /%year%/%monthnum%/%day%/%postname%/
Active Theme: pg18+buy 1.3.0

Test Mode Enabled: No
Ajax Enabled: Yes
Guest Checkout Enabled: No
Symlinks Enabled: No

Checkout is: Valid
Checkout Page: http://pg18plus.com/buy/checkout/
Success Page: http://pg18plus.com/buy/purchase-confirmation/
Failure Page: http://pg18plus.com/buy/checkout/transaction-failed/
Downloads slug: /downloads

Taxes Enabled: No
Taxes After Discounts: No

Registered Post Stati: publish, future, draft, pending, private, trash, auto-draft, inherit, refunded, failed, revoked, abandoned, active, inactive

Platform: Windows
Browser Name: Chrome
Browser Version: 29.0.1547.76
User Agent String: Mozilla/5.0 (Windows NT 6.2; WOW
64) AppleWebKit/537.36 (KHTML, l
ike Gecko) Chrome/29.0.1547.76 S
afari/537.36

PHP Version: 5.3.22
MySQL Version: 5.1.70-cll
Web Server Info: Apache/2.2.24 (Unix) mod_ssl/2.2.24 OpenSSL/1.0.0-fips DAV/2 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 mod_jk/1.2.35 mod_antiloris/0.4

PHP Safe Mode: No
PHP Memory Limit: 256M
PHP Upload Max Size: 2M
PHP Post Max Size: 8M
PHP Upload Max Filesize: 2M
PHP Time Limit: 30
PHP Max Input Vars: 1000

WP_DEBUG: Disabled

WP Table Prefix: Length: 3 Status: Acceptable

Show On Front: page
Page On Front: Get The Most Advanced Fun Sharing Script (#2)
Page For Posts: (#0)

WP Remote Post: wp_remote_post() works

Session: Disabled
Session Name: PHPSESSID
Cookie Path: /
Save Path: /tmp
Use Cookies: On
Use Only Cookies: On

WordPress Memory Limit: 40MB
DISPLAY ERRORS: On (1)
FSOCKOPEN: Your server supports fsockopen.
cURL: Your server supports cURL.
SOAP Client: Your server has the SOAP Client enabled.
SUHOSIN: Your server does not have SUHOSIN installed.

TEMPLATES:

ACTIVE PLUGINS:

Contact Form 7: 3.5.2
Easy Digital Downloads: 1.7.2
Jetpack by WordPress.com: 2.4.2
WP Super Cache: 1.3.2
### End System Info ###

[Moderator Note: Please post log files between backticks or use the code button.]

http://wordpress.org/plugins/easy-digital-downloads/