I see two issues. First, you don't have any sets of parenthesis in your regular expression which means \1, \2 and \3 are not set to anything. Which means they print as string literals. You know the reg exp is matching something since it doesn't return Invalid.
This example prints "folder". "0" is a special match that means the whole match regardless of parens.
The second issue is that you aren't matching projectname. That's easy enough to solve. Just add to the regular expression. And add parens so it is the first match.