Been trying to work with SubProducts, but I still can't figure out a few things:

1.) How do I make "Variations" show up in the product? I have created a "variation" (Finishes) with a few attributes (Chrome, Antique, etc) but I can't see any integration in the Content Type or Node. How do I assign it to the nodes that need it? This isn't obvious.

And 2.) In attributes, I'd like to add a percentage instead of a fixed charge to it. (i.e., "Chrome" attribute adds 20% to the cost of product). Could I do it like this: [product:total] * 0.20? Suggestions?

More worrisome, I am getting this error when trying to upgrade to the "latest" version:

An unrecoverable error has occurred. You can find the error message below. It is advised to copy it to the clipboard for reference. Please continue to the error page.

An error occurred. http://www.domain.com/update.php?id=61&op=do <br /> <b>Warning</b>: Call-time pass-by-reference has been deprecated in <b>/home/user/domain.com/sites/all/modules/ec_subproducts/ec_subproducts.install</b> on line <b>26</b><br /> { "status": true, "percentage": 100, "message": "Remaining 0 of 1.\x3cbr/\x3eUpdating video module" }

I've uninstalled and re-installed both the dev version and the rc4 version, but still get this error:

Warning: Call-time pass-by-reference has been deprecated in /home/user/domain.com/sites/all/modules/ec_subproducts/ec_subproducts.install on line 26

Any help would be appreciated.