Thats Odd... I do't actually check for existence of the music file...
So what I do is I extract the LSP sequence, which is really a 7z archive with a file called "Sequence" and a sub directory called "controllers". I then start to process the Sequence. The first step is to process the Sequence file to find out about the sequence I am converting. in this case it seems to be implying that there was no file named "Sequence" In the archive I am processing... Perhaps post the msq file and I can take a look.
Frank