WHDLoad causing havoc

For the first time in many years, I decided to install several games on my HDD, using whatever means necessary. In most cases, those means turned out to go by the name WHDLoad. However, I've encountered the oddest of problems:

My system (an A2000) runs a 16 bit Workbench in 800x600. I've grown used to that resolution, and kind of like the thought of keeping it that way. This is made possible by using a Picasso II+ and P96 in conjunction with a scandoubler.
Now, what happens with WHDLoad is that it presents me with a black screen and a frozen pointer. Other than that, most games seem to run fine. And I can even make a clean exit with F10. Obviously a problem with the screen resolution. Once I've stated this, it's getting interesting: Setting the tooltype PAL makes no difference whatsoever. Setting the tooltype NTSC, however, gives me a working screen in - NTSC. It beats a black screen of course, but on a PAL-system it doesn't really provide me with an enjoyable gaming experience. Unless, of course, I'm on acid - which I'm usually not. And before anyone asks - yes, I've got the PAL file in Devs:monitors. Might also add that when run outside the Workbench, the games concerned work just fine. Other than that, I can't really say much besides, perhaps, help?

EDIT: Problem solved.

System setup:

A2000
Blizzard 2040/40Mhz with 128Mb FastRAM
Scandoubler
PicassoII+ (2Mb)
ROM 3.1
AmigaOS 3.9