First up, do you want New Practical Chinese Reader, or just Practical Chinese Reader flashcards? If it's for NPCR, then I can help you out with a complete set of books 1 - 3 that I typed in myself. If it's the PCR ones, then I can't help much with free flashcards.
In any event, to get it working, just synch it to your device. To Internal Memory. Then open up PlecoDict, open the menu, select 'Flashcards', and then 'Manage Flashcards'. Select 'Import', and make sure the file-type is PalmDoc. Probably set the encoding as UTF-8, but I'm honestly not sure what it would be. If that doesn't work, report back.