HTML5 Canvas: adding "Go to Web Page" code snippet makes browser display nothing when testing

Hello! I'm working on an animated, interactive infographic in an HTML5 canvas document. I have a series of buttons that I intend to make open and close a corresponding series of infoboxes. This I've figured out how to do already; they work fine. What I'm hoping to do now is make certain parts of the text within these infoboxes link to web pages. The idea is simple: click a button, infobox above button appears, click text within infobox, you're taken to website. When I apply "Click to Go to Web Page" from the "Code Snippets" panel to the specific piece of text I want to make into a link, the browser displays nothing when I execute "Control > Test". I thought there was something I did the application didn't like, something to do with how I have things nested, etc. However, it seems the problem is way more simple than that. Before adding the Go to Web Page code snippet, the test works fine. I try adding a simple shape in Scene 1, at the top of the hierarchy, and apply the Go to Web Page code snippet, and, again, the browser displays nothing. Here's something weird: when I open the file, the test works fine, as I've not added any code snippet. I add the code snippet, run the test, blank browser. Now, when I undo back to before I've done anything, like it was when I opened the file, it does the blank browser thing again. That's baffling. Please help me. Also, I should mention, when I try to test on one of my computers, I get this message in the otherwise empty browser window: Error 404: Not Found File not found. Testing works fine on my desktop computer, however. Thanks! (Okay, apparently, I can't attach the Animate document to this message, even though it says that .fla files are supported, so what's up with that, btw? I'm about to lose my mind here.)