Hello @
kevinrm ,
As I see, our support team has already upgraded the store for you. Happy to know that your store is up again.
As for the problem with failed upgrade, there is indeed a problem that caused by incorrectly updated modules. We sent a newsletter to each X-Cart 5 developer, so they would check their modules and adjust them if needed. Here is an instruction about updating modules in case somebody needs it:
http://kb.x-cart.com/display/XDD/Updating+modules+from+5.1+to+5.2+branch