php error

Hey, I just installed your plugin which looks like it will be perfect. But when I went to my cart I received the following php issues at the top of my site:

Warning: rename(/home/smerchst/public_html/wp-content/uploads/woo-designer/91e9b1beb92d0f295f90ffec1b8cf9bc/387_front.png,/home/smerchst/public_html/wp-content/uploads/woo-designer/91e9b1beb92d0f295f90ffec1b8cf9bc/387_12400301805ec25cc3e8c797.92673554_front.png): No such file or directory in /home/smerchst/public_html/wp-content/plugins/woo-shirt-product-designer/shirt-product-designer-for-woocommerce.php on line 608

Warning: rename(/home/smerchst/public_html/wp-content/uploads/woo-designer/91e9b1beb92d0f295f90ffec1b8cf9bc/387_back.png,/home/smerchst/public_html/wp-content/uploads/woo-designer/91e9b1beb92d0f295f90ffec1b8cf9bc/387_12400301805ec25cc3e8c797.92673554_back.png): No such file or directory in /home/smerchst/public_html/wp-content/plugins/woo-shirt-product-designer/shirt-product-designer-for-woocommerce.php on line 609

Warning: A non-numeric value encountered in /home/smerchst/public_html/wp-content/plugins/woocommerce/includes/class-wc-cart-totals.php on line 227

Warning: Cannot modify header information – headers already sent by (output started at /home/smerchst/public_html/wp-content/plugins/woo-shirt-product-designer/shirt-product-designer-for-woocommerce.php:608) in /home/smerchst/public_html/wp-content/plugins/sg-cachepress/core/Supercacher/Supercacher_Helper.php on line 68

I have currently disabled the plugin. Is there a way to resolve this please?

Thanks