Php shopping cart debug

i need some help to debug a shopping cart script on my local machine, the online store is working except for some bugs on add to cart and on checkout process. its based on PHP only and the script was written my myself. I wil provide you a remote access to my computer in order for me to be able to show you where the errors are, as well will be provide the link where the files are published for live test. if you are expert in php and can fix this problem i will be glad to deal with you.
please get in touch.

this is some specification about what i need to get done:

* review and correct some errors in the shopping cart script
* review and ensure the variables values like shipping price, product quantity etc are correct and ensure it pass the values without any errors to the checkout process.
* saving the information in the database, send the email confirmation with order details.

* review the code on local machine and then on the live server.

basically you gonna have to to through the code in the specific bags which i will show you and correct them.