Product Addons Premium WRONG TOTAL ON PAYPAL

Hi,
I’m having a couple weird issues with the Product Add-ons Premium jigoshop plugin:

1.- When trying to check out and pay via paypal, jigoshop displays the correct total, but then paypal shows an incorrect total (that I’ve deciphered to be the base product price + all addons total x 2)

2.- When trying to add a product add-on (not a global one) after clicking Update/Publish
I get redirected to a page not found (/wp-admin/post.php)

Please help us!, we’re supposed to launch this very important site for a multinational client and we’re completely stuck here

Best regards,
Nicolas.

### Begin System Info ###

	Multi-site:               No

	SITE_URL:                 http://rusty.3amdesign.net
	HOME_URL:                 http://rusty.3amdesign.net

	Jigoshop Version:         1.8.5
	WordPress Version:        3.9

	Platform:                 Windows
	Browser Name:             Chrome
	Browser Version:          34.0.1847.116
	User Agent String:        Mozilla/5.0 (Windows NT 6.2; WOW
                                  64) AppleWebKit/537.36 (KHTML, l
                                  ike Gecko) Chrome/34.0.1847.116
                                  Safari/537.36

	PHP Version:              5.3.28
	MySQL Version:            5.5.32-31.0-log
	Web Server Info:          Apache

	PHP Memory Limit:         256M
	PHP Post Max Size:        32MB
	PHP Upload Max File Size: 24MB

	WP_DEBUG:                 Disabled

	WP Table Prefix:          Length: 3 Status: Acceptable

	Show On Front:            page
	Page On Front:            5
	Page For Posts:           0

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

	WordPress Memory Limit:   40MB
	WP_DEBUG:                 Off
	DISPLAY ERRORS:           On (1)
	FSOCKOPEN:                Your server supports fsockopen.

	ACTIVE PLUGINS:

	AJAX Thumbnail Rebuild: 1.11
	Akismet: 3.0.0
	Contact Form 7: 3.8
	Developer's Custom Fields: 0.9
	Disqus Comment System: 2.74
	Jetpack by WordPress.com: 2.9.3
	Jigoshop: 1.8.5
	Jigoshop Product Add-ons Premium: 1.9.3
	Post Types Order: 1.6.8
	WP Migrate DB Pro: 1.3.2
	WP Migrate DB Pro Media Files: 1.1.1

	CURRENT THEME:

	Rusty Theme by 3amDesign: 1.0.0

	### End System Info ###

https://wordpress.org/plugins/jigoshop/