There's a total path length limit in windows. For most practical purposes this limit is 240 characters. I *think* in MC it ends up being 259 characters. If you now have longer path names on your new computer due to having moved your music files to a new location or something else, that would explain why they won't import. Do these files have very long path names? Or very long file names?
You could shorten the directory path and if that gets you under 240 total characters, it should then import. If you want specific help, please post the full path and file name to one or more of your problem files.
Good luck.
Brian.
