In a string literal you should always escape "\" characters with another "\" character like this:

loadMovieNum("subFolder\\myMovie.swf", 5);

Alternatively you can use the "/" as a path separator like this..

loadMovieNum("subFolder/myMovie.swf", 5);

Check out section 4.5.2.2 "Escape sequences" from Colin Moock's book, ActionScript : The Definitive Guide. You can read the relevant section online at http://skaiste.elekta.lt/Books/O'Rei...on/ch04_05.htm