This may help for the black screen.... if it doesnt, you may have some problem with either our graphics drivers being out of date, or direct X not working properly.
The imp hero cut scene, has been encountered before by some, so its not something unheard of (unfortunately), it is avoided by either ending the conversation using the X in the dialog screen, or by the DK waiting in some other corner of the universe. (Congratulations for figuring that one out - you definately clever enough, since MOST people just get stuck there and cant figure any way around it)
The mini map (am i right to assume that it happens in the battlefields?), is a known issue, because the battlefields are so big, the map is segmented and sometimes the segments dont load properly.
As for the main map, i have only encoutered that once or twice, and both times when i clicked on A (automap) and then returned, my screen was fixed again....
