Well, to debug this, you would first need to see what is inside $source[‘path’] and make sure it is a filename that is the correct one. And, you need to force the correct folder into the variable, too.
Did you have the folder name in the “?” part? if not, you need to add it in. One way to debug all this is to just run the process again and echo the $source[‘url’] right after the line you showed. Make sure that is formatted exactly as you think it should be. My guess is that either the $source[‘path’] is not a valid file that actually exists at this point in the code which would mess up the filectime() results.
But, what is the @ sign doing in a time conversion line? I mean, you get a file name, get the creation time of that file and use it in the source url. If you are trying to access a folder named by a creation date, then
this makes sense. Otherwise, this line makes no sense. But, the @ sign can not be used in a folder address… I will download the script and look at the original code. Perhaps I can tell what you need here.
EDIT: Which module is this line found in? Too many files to look thru!