Talk about RBAR on steroids and overcomplicating things. These cursors are just going row by row adding a value. This is totally unnecessary if you know about aggregate functions. In this case, you're looking for SUM().
Please show us what have you tried.
Luis C.
General Disclaimer:
Are you seriously taking the advice and code from someone from the internet without testing it? Do you at least understand it? Or can it easily kill your server?
How to post data/code on a forum to get the best help: Option 1 / Option 2