Which version of FrostWire are you using?
If it is version 5 or later, it is the torrent only version which we are unfortunately unable to help with (because we know little to nothing about the torrent only version which does not connect to the gnutella network.) In which case you could post an issue to the FrostWire project at SourceForge or contact the developer through the links at the FW website.

It's my guess your settings might have been set to default during the update but your files are still there (and incomplete files if that's the case.) So it might be a matter of setting your download and shared file locations to what they were previously.