Rich,
I also get a black screen in my Windows port, so this is starting to look like another case where the DOS and Xfractint code bases are rendering differently.
Not sure what's causing it...
I haven't found the cause. What I have seen is that if you start Fractint with debug=2870 to force use of the 80287 code, the bug appears. This is true of the other par file I'm looking at, as well. I've been thinking that this is caused by some variable(s) not being initialized, but it may be due to a function being implemented as foo{}. This would be likely for the Xfractint code, not so likely for the FPU < 387 code. Also, if Fractint is started normally and then switched to debug=2870 using the <G> screen, the image continues to generate normally. Still looking. Jonathan