just added pluging WPtouch - broke site?

Hi,
I just added a plugin called WPtouch to help make the theme more mobile friendly, but after completing the settings of the plugin and testing the results it seems to have broken the site?

Could someone please see whats gone wrong and help resolve it please? - http://take.ms/EDWE0

(Broken when tested on mobile device? but loading ok on desktop??)

Domain - http://tinyurl.com/ounlhnf

Fatal error: Call to undefined function storefront_sanitize_hex_color() in /home/*********/public_html/shop/wp-content/plugins/storefront-designer/storefront-designer.php on line 763

for file see pastebin expires in 3 days - http://urlgone.com/e925a4/

Support Access is open

Thanks

Tom