Did you change monitor since you last started it? Seems like the set resolution + refresh is not supported by current one.
Think you can set the res in an .ini somewhere, I'll has a look.
* should be "main.cfg" in SH4 folder in "my documents". For me it reads:
1280,960,85,22 (width, height, refresh, ?)
Try 1024,768,60,(whatever it says for you on the last number), or maybe delete the numbers alltogether, good chance the game will default to 1024*768 (if it doesn't you know where to look
)