FATAL ERROR beim öffnen vom Warenkorb..

Wir haben gerade diesen Fehler im Shop: 

 

Fatal error : Uncaught InvalidArgumentException: Input must be numeric. in /kunden/486365_80797/shops/liveshop/engine/Library/Enlight/Template/Plugins/modifier.tax.php:35 Stack trace: #0 /kunden/486365_80797/shops/liveshop/var/cache/production_201801171346/templates/frontend_MimeEtMoi_en_GB_2_secure/49/56/de/4956deca9110721c1be3913b1de4506e03e631c4.snippet.index.tpl.php(5104): smarty_modifier_tax(NULL) #1 /kunden/486365_80797/shops/liveshop/var/cache/production_201801171346/templates/frontend_MimeEtMoi_en_GB_2_secure/49/56/de/4956deca9110721c1be3913b1de4506e03e631c4.snippet.index.tpl.php(1790): content_5b86801b37c8a1_21869800(Object(Enlight_Template_Default)) #2 /kunden/486365_80797/shops/liveshop/engine/Library/Smarty/sysplugins/smarty_internal_templatebase.php(180): content_5b86801b5404a6_02662638(Object(Enlight_Template_Default)) #3 /kunden/486365_80797/shops/liveshop/engine/Library/Enlight/View/Default.php(276): Smarty_Internal_TemplateBase->fetch() #4 /kunden/486365_80797/shops/liveshop/engine/Library/Enlight/Control in  /kunden/486365_80797/shops/liveshop/engine/Library/Enlight/Template/Plugins/modifier.tax.php  on line  35

Kann mir jemand helfen? 

DANKE!