Version 4.8.1 not sharing files

Have been using the latest version for several days and it was running fine until the popup which always appears with the message "....Limewire is not your default magnet handler..." I clicked 'ok' just to get rid of it. Now, I can no longer add or remove files to share - that option is frozen when I click on add file and also the tools option. Can't figure this one out - very, very odd. Have tried uninstalling, using a previous version and now have redownloaded and the same thing is happening. (running XP on 56k). Thanks for any advice.