Why can't I add torrents to BT now I've switched to a Mac?

[Guest Emma]

Hi, I used BT on my PC for the last five years, recently switched to a Mac and downloaded the Mac BT today... BT installed and opened ok, but the torrent I wanted to add just won't add, no matter what I do - I've tried opening a torrent using the add button on BT, I've tried dragging and dropping the torrent file into BT, still nothing... at a bit of a loss now... Please help! P.S. The torrent has plenty of seeds, so don't think that's the issue! Thank you!