I found out the source of your problem!
In your instrument bank it seems you deleted a couple instruments. I could tell because it goes from instrument 27 to instrument 2A without any instrument 28 or 29. Turns out NESmaker gets REALLY confused when it reads that and goes nuts with error messages. What you should do: Add 2 more instruments to fill slots 28 and 29 back again.
Now looking at your music and instruments, I noticed a few things that shouldn't cause too many issues, but it would be wise of you to fix.
1. The main thing I notice is that at the end of your NauseousWaltz song you use the Dxx effect, which isn't supported by NESmaker or GGsound. Now, normally effects shouldn't PREVENT the song from importing, it just wouldn't do anything when it plays. HOWEVER, since the Dxx effect could cause issues with how the song itself plays, so you should probably remove it.
2. A small thing I noticed is that your SFX don't have stop notes at the end of them. What I would do is create an instrument with a volume envelope of 0 and place a note at the end, followed immediately by a note break (AKA a dash - ). That will make absolutely sure the SFX ends and the music on that channel will play again.
3. This probably doesn't effect much, but it would be a good idea to make sure ALL of your instruments have a Duty envelope, half of them don't.