what firmware are you on? I haven't tried the bluetooth transfer with the latest version (I confess I gave up on that with the previous firmware, as it was too erratic), and cannot give it a go now as I am travelling with the PB360, having left the PB903 at home, but I'll try when I am back. With the previous version, J.C. gave precise instructions, and tehre were some tips from the russian forum. You wil find the three links at the bottom of the top message (under "Connections") in the "User tips..." sticky thread
. Hope some of them work!
Another alternative for file transfer is via the web. You can upload your library in Dropbox (well, you need a dropbox account: if you don't have one, you can create one for free with 2GB space, and if you create it by clicking the link in my signature, we both get extra space, 250MB if you have any email accoutn, whihc become 500MB if you have an .edu or other academic email account when signing up with dropbox). You then open your browser in the PB902 and go to the dropbox mobile (just type in the address "https://www.dropbox.com/m/"), which is a lighter version, and download the file you want from your library. In this case you never need to connect the device to your computer.
You can also be a bit more sophisticated by creating a Calibre catalog and opening that one to find the book you want, and then download it on your device. To create the catalogue you need Calibre2OPDS (see here
Hope it works!