[plug-in WP e-commerce] checkout error

I am using the WP e-commerce plug-in and I have 2 issues.

1- when ever I manage a product and press the “edit product” button, I get redirected to an error page that reads:

Warning: include_once(/home/content/t/o/u/toughstufforg/html/wp-includes/class-IXR.php) [function.include-once]: failed to open stream: No such file or directory in /home/content/t/o/u/toughstufforg/html/wp-content/plugins/wp-e-commerce/processing_functions.php on line 1114

Warning: include_once() [function.include]: Failed opening ‘/home/content/t/o/u/toughstufforg/html/wp-includes/class-IXR.php’ for inclusion (include_path=’.:/usr/local/php5/lib/php’) in /home/content/t/o/u/toughstufforg/html/wp-content/plugins/wp-e-commerce/processing_functions.php on line 1114

Fatal error: Class ‘IXR_Client’ not found in /home/content/t/o/u/toughstufforg/html/wp-content/plugins/wp-e-commerce/processing_functions.php on line 1117

What does all this mean? I can’t find the processing_functions.php to check it out. The changes to the product description remain after leaving this error page, so I don’t know what damage this is doing.

2- After headaches with PayPal, I switched to google checkout. When I press the GoogleCheckOut button, all I get is an error page that reads “Oops! We were unable to process your request.” I do not have an https URL to paste into googles codes, but I do have the http. Could this be my issue? or does my 1st issue cause this? OR (one more) would an incorrect list of information of my bank account on Google’s records cause such an error?

Thanks for ANYONE’S help!!