Try a different midi file. Maybe Journeys.mid is corrupt. Because the test program worked, there shouldn't be anything wrong with the commands to load and play the file. The most likely culprit is either the file itself, or you are somehow not identifying the correct directory where the file lives.
Try this:
Start a new empty program and run it (F5). It should open the command line interface (CLI) - a black screen with a yellow bar and > prompt in the bottom section.
at the '>' , type
a$=get dir$()
press [ENTER]
Then type
print a$
press [ENTER]
At the top of the screen, the full path of your current working directory should print. Memorize or write this path down exactly as it appears.
press [ESC]
Copy your midi file into the directory you just wrote down. This is the current directory DarkBASIC is looking at when it starts. Once your file is copied, in an empty program, copy and paste:
sync on
myfile$="Journeys.mid"
if file exist(myfile$)
text 0,0,myfile$+" has been found."
while spacekey() ! 1
rem stay in loop until space key pressed
text 0,20,"Press space key to load and play"
sync
endwhile
load music myfile$,1
loop music 1
else
text 0,0,"the file "+myfile$+" has not been found"
endif
sync
If you have moved the midi file into the correct directory, this program will tell you that it has found the file and prompt you to press the space bar to load it. If it doesn't, then the file is not in the correct directory, or the name of the file referenced in the program is different. Check to make sure they are spelled the same way.
If it finds it, you press SPACE, and it still doesn't load and play, there is something wrong with the file itself.
In answer to your second question, a 3d model should be in Direct X format (.X extension) or you can get away with older 3d studio files (.3ds extension). DarkBASIC Classic is old so the direct x version is 7. This means that for animation, a hierarchical structure is necessary. Bones/skeletal animation cannot be used.
Enjoy your day.