I don't understand your second question. Do you mean what is the best application to transfer document to your Pearl? That would your PC, with Mass Storage enabled on the Micro SD media card. Drag and drop to from the PC to the card.
ok, "refuses documents": details of what you are trying to do might be helpful here.
You cannot save "documents" from an email to the SD card. You can move them from the PC to the card if mass storage is enabled. You can't read or open just any "document" or open it, from the SD card to the BB.
Let me rephrase my question: What exactly are YOU doing on your PC or the BlackBerry when the "transfer failed" message occurs?
Please, describe in DETAIL the action you have just performed, such as "I have my BlackBerry connected via a USB cable to my PC. I dragged the file from my PC to the SD card using Windows Explorer, but after I drop the file, I get an error message TRANSFER FAILED". Yes, complete sentences will help.
I really am trying to help, but it is frustrating.