in the webassist/shopping_cart/store_cart.php
change line 37
$WA_columnTypesStr = "none,none,NULL|none,none,NULL|',none,''|',none,''|',none,''|',none,''|',none,''|',none,''|',none,''|',none,''|',none,''|none,none,NULL|none,none,NULL|',none,''|none,none,NULL|',none,''|',none,''|',none,''|',none,''|',none,''|',none,''|none,none,NULL|',none,''";
to:
$WA_columnTypesStr = "none,none,NULL|none,none,NULL|',none,''|',none,''|',none,''|',none,''|',none,''|',none,''|',none,''|',none,''|',none,''|none,none,NULL|none,none,NULL|',none,''|none,none,NULL|',none,''|',none,''|',none,''|',none,''|',none,''|none,none,1|none,none,NULL|',none,''";