Error on line 325

Hello,

I've been trying to make work this module but without success. I followed the video, but when I Add Product, the Price table widget does not appear, and instead the Add New Variation remains. When I add the price to the New Variation then save, I receive the following message:

An AJAX HTTP request terminated abnormally.
Debugging information follows.
Path: /system/ajax
StatusText: n/a
ResponseText: Fatal error: Cannot access empty property in /hsphere/local/home/WEBSITE/modules/field/field.attach.inc on line 325
ReadyState: undefined

After this, I save the product and check if it was created, however, the table does not appear neither in the node or teaser. Also when I try to Edit the node I receive the following message:

Error message

Notice: Undefined index: in _field_invoke_multiple() (line 310 of /hsphere/local/home/WEBSITE/modules/field/field.attach.inc).
Notice: Undefined index: in _field_invoke_multiple() (line 310 of /hsphere/local/home/WEBSITE/modules/field/field.attach.inc).

Fatal error: Cannot access empty property in /hsphere/local/home/WEBSITE/modules/field/field.attach.inc on line 325

I tried to install this module in a new installation of Commerce Kickstart 2.0. I used both the 7.x.1.x-dev and version 7.x.1.1 but none of them work.

Any help will be much appreciated.

Thanks,

Andrew