The Create Folder action will not always succeed. See here or a couple of other posts for details.
What I'd really like to do is find some way to still move and rename the screenshots even when they include the date information at the end of them.
Not sure what you mean. If the date information (as part of the file name) is subject to change, then you must exclude it when selecting the files to move by name. For example you can test for files whose basename begins with “Screen Shot” and whose extension is “png”, or whatever.