keep in mind that the backslash '\' works as an escape character to get special characters (like tabs, newlines) and to get a real backslash, you have to use a double backslash. This will make your paths look weird ('c:\\bioperl\\project').

You do not seem to understand the difference between single and double quoted. What you said is true for double quoted strings, but even in your example you use a single quoted string. No need to escape the backslash there - it would only need to be escaped if it's at the end of the string, or if followed by a backslash. None of that is happening in the OPs path.