I created a new project and had the same problem with that same file so I think there is something wrong in the file.
I opened the file in wavosaur editor and everything seems to be ok. I saved the file with different name and now the new file can be imported into the project without any problem.
Then I opened the properties windows of these files and the only difference I can find is the bitrate value. The file that couldn’t be loaded doesn’t have any value and the new file saved by wavosaur has value 1 058 kbps.
