Out of memory error

For some reason when clicking on one particular product on my site I get the following error


Fatal error: Out of memory (allocated 66584576) (tried to allocate 54 bytes) in /websites/123reg/LinuxPackage99/to/ta/l_/total-martial-arts.co.uk/public_html/libraries/joomla/database/database/mysqli.php on line 675

Is this a Hikashop error? All other products are fine, I can add more products without errors, I have deleted this item and created it again, I have tried different images etc but still get the same error. Any ideas?

Here is a link, its the 'macho dyna combat kit' that produces the error, www.total-martial-arts.co.uk/index.php/s...protective-equipment

I have deleted and recreated the product but it still does the same, i've tried to take out the description but that doesn't make a difference either, I get an internal server error when trying to edit this product in the backend too. All other products are fine.

Its that characteristics causing the problem....i need to add 5...the product is fine unless I add these 5 variants....I need customers to be able to choose the colour and then there are five items that need a size option, but each size option is different, how do I use custom fields?