Maybe it was pulsar? I dunno some NES program I ran into had trouble due to using an odd mapper. That said, your version of VegaPlay (http://forums.nesdev.com/viewtopic.php?f=6&t=11322) /does/ indeed work with PowerPak. I used your example .NES and I noticed some songs would cause the NES to freeze. I'm guessing it's because the NSF didn't actually have song data there or something?
I don't have a 6502/NES toolchain setup yet so that's next on my list, at which point I can do additional tests. But apart from the freezing issue, yeah it worked like a champ! I'm guessing any sync additions you plan on adding should work fine too, but of course if you add them, let me know and I can easily test them on my PowerPak.
Could be Pulsar, it uses SXROM which is an extremely rare mapper ( only used in one Famicom title)
Good to hear the mod does work on your HW Yea some of the NSFs I grabbed are 'weird'. I think they use a different tool chain/tracker and stomp on some of the ram I'm using. FamiTracker NSFs work fine so not too motivated to find a fix for every driver out there. VegaPlay has the same issues outlined in the release notes.
The tool chain is a breeze, the release package will have a copy of ASM6, the compiler. No install, just configure the user config file and run the .BAT
Yogi