Activate plugin

Halli, I can’t activate the plugin. First Plugin Page stays blank and after I deleted all the plugins and uploaded only the wp-ecommerce plugin, I get this: Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 122880 bytes) in /home/glosszen/public_html/wp-content/plugins/wp-e-commerce/wpsc-updates/currency_list.php on line 14 (and other lines.

How can I solve this?

https://wordpress.org/plugins/wp-e-commerce/