Oh junk. Sorry, I tried not to be a newb about this, but I was rushing and didn't even include the circumstance when it happened!
Okay so ... the crash happens when I enter a battle with a party member with 0 MP. And yes you are right Fall from Eden, it is a divide by zero error in the code for processing the battle HUDs, I believe. Line 443:
self.contents.gradient_fill_rect(x+7,y+37,(width-14)*actor.mp/actor.maxmp,3,
mp_color1,mp_color2)
I am not a scripter (I am reading Rafiki's Tutorial on Ruby and enjoying it, though), so I do not know if there is an easy way to check for a clause should it be zero, and make it one instead. One funny thing I noticed when testing my 2nd problem: Many enemies have 0 Max MP, and don't have this issue (their HUD displays correctly).
The 2nd problem, I duplicated and isolated the error, it must be a compatibility issue with the "Make BGM unchange 1.01 by ERZENGEL" script if found
here, designed to prevent BGM from changing during battle processing. Something must be overwriting something else and not accounting for the window that is drawn during combat resolution.
Download links:RMVX project duplicating the errorErzengel's Make BGM unchange scriptAny help or advice is appreciated! I'm trying to be as helpful as I can.