tried adding .pdf label export

I tried making a few modifications to the Contact Directory module.

1. Modifying some of the fields
2. Adding .csv export functionality
3. Adding an export for labels in .pdf format

The first two went pretty smoothly, but the I'm having trouble creating the .pdf document. Everything seems to work out OK, but the file is unreadable. I am using the R&OS pdf class

• Does anyone know if, when including php files, the <?php and ?> have to be left out? Also, has anyone else already done this? I searched this site and couldn't find any reference to it.
• Also, where can I get a list of variables that Drupal uses so that I can see if there's a conflict with the variables that the pdf class is using?

You can find a copy of my modified module at januario.com

Any help would be greatly appreciated.