I searched the forums and found this. I'm having trouble with Iggy's Reckin' Balls as well.
Using Project64 1.6 (the current version) with the latest RDB files. I think it's the GoodN64 version. It came in a .7z file with the (E) and (J) files, as well. I only tried the (U) file.
I launched the game with cheats to get all characters and tracks (though there seems to be one character still locked). And after the first track, I think, the game went to the black screen and wouldn't come back. I have since tried to go to other races. I went to Race 5, which is Funkytown, or something. And it wouldn't start. It went to the black screen after the race select. I have sound turned off, so I don't know if the sound kept playing. But the game didn't come back.
I tried the older version of Jabo's Direct3D plugin (1.5.2) and that didn't help. I tried Unofficial DaedalusD3D8 0.08 Rel. 3. And that didn't work, either.
A couple times the game did show the Progress screen, then it went to the black screen. I tried different suggestions in the thread, along with messing with other settings. And it didn't work.
I don't know if it's because I'm using the character "Mask" or what. I'm hoping that some solution can be found. Unless something already was found and I'm not seeing it.