After I did not receive any erroro messages yesterday- today I discovered the product-page is somehow missing and evrytime I try to save a picture the page type switches to 'accountpage'. Weird.
I tried the code mentioned by bambii7 (http://silverstripe-ecommerce.googlecode.com/svn/trunk/code/products/Product.php) (copy-paste is a wonderfull invention)
and so far it seems fine...
33 mins later:
nope, did not work. I took out _extendedproductvariations and _anypriceproduct but still have the backswitch to AccountPage. bäh.
producing a new ProductPage saves at least the image, but after going to the stage site I got this : Fatal error: Call to undefined method ShoppingCart::get_item_by_id() in C:\Programme\wamp\www\silverstripe\ecommerce\code\products\Product.php on line 240
I tried setting up my first ecommerce silverstripe site a few weeks ago and found out that it wasn't quite all there.
I haven't been using any of the other ecommerce extensions "ecommerce_extendedproductvariations" only the latest release of ecommerce from that googlecode link. And the most recent Payments module down loaded from the extensions. There were a few errors to fix but mostly looking good.
The other modules and ecommerce module are only compatible on ss 2.3 (I think don't quote me) but from what I can tell the google code ecommerce project is getting updated daily. I don't think its intended to be used on a live site just yet. But you should be able to set up the old ecommerce module on an older version of ss with the modules you needed.