Morning Marie,
 
I'm just going to throw this out there because I just did this a couple days ago  
 
I would change the widget parameters and get the HTML code, and kept getting the general card store...I was forgetting to hit the save button before getting the HTML.  
 
HTML can sometimes be stubborn.   If you haven't thought to do so yet, try deleting the module on your blog where your widget was, save the blog and then add a new module back in and enter the widget code.  Sometimes that works when HTML is acting up.
 

Well, no ideas to fix you up, but I can confirm its a glitch and not just you.
 
Though my widgets are working fine, I did just go to my GCU Widget creation page and looked at the code.  My store number is not in the code either for the widget, so if I were to take that code and create a new widget, it would work as yours is, going to the homepage.
 
So this will need to wait until Shaun can help and in the meantime, other artist's should probably refrain from attempting to update their existing widgets or adding new ones until this can be fixed.
 
Not very helpful, I know  

I know, you're always a good girl Marie  
 
Well, the post is made in the Support thread and your Subject is quite clear, so I guess if it was me I'd hand tight, though it will probably not be till Monday before Shaun sees it  

Sorry the delayed reply on this topic.  We're looking into this.  
 
Shaun

sorry Shaun, no luck, just can't get it to work.