CSS3pie - styles not being picked up in IE. How to reference the path?
The PIE Drupal module should add the behaviour where necessary, you don't do that yourself. This would defeat the point of the Drupal module, and in using the Drupal module you don't need to specify the path yourself. (Though your current path there is incorrect, but I'm not sure on the correct way right now.)

css3pie can seem very touchy, there is a long list of known issues, some of which could be causing your problem. Also ensure that your files directory is writable, and that there are no errors on your sites status page. File permission problems can prevent the css3pie module from creating it's stylesheet. Each setting in the themes .info file should also be on a new line.