Ok I transfered 1700 books on my PRS-505 reader, some on the reader and the rest on a 2Gig SD, which are organized in 110 collections, but once I deconnect the reader from the eBook Library it keeps reseting over and over again, like it is not able to process such a big list.
I plugged it back into the Library and all my collections have been wiped on the SD card, but the books are still there.