When installing a third-party plugin today (WP-Client) my site got disabled with a fatal error.
Fatal error: Cannot redeclare pe_network_gateway_settings_box() (previously declared in /home/prints/public_html/wp-content/plugins/WP-Client/includes/payment_gateways/paypal-express.php:876) in /home/prints/public_html/wp-content/plugins/marketpress/marketpress-includes/plugins-gateway/paypal-express.php on line 1366
Seems WP-Client and Marketpress have a function name conflict. I informed them of this issue, and am doing the same for you.
I'm not concerned with a solution (I'm sure I can sort this out myself) but I wanted developers to know.