This link has a lot of interesting applications including conv3ds.exe.
3ds to X
or
basic 3ds to X
Do you have the 3ds file that is giving you the problem? I can see the picture you've supplied, but it's hard to trouble shoot with just an image.
One other thing to try, try downloading
Deled. There's a free version and it is an excellent level builder - and the X export works great with DarkBasic. I think there is even a DarkBASIC Pro export option, but I've never used that because I use DarkBASIC Classic.
Also, at one time I was using Anim8tor to do the UV texturing on my models, exported them to 3ds, Imported them into Deled - then just exported them back to X from Deled to use with DarkBASIC. Deled was also very handy to adjust models to the proper scaling I wanted. I think I was running into problems with the 3ds export in anim8tor as well, though I can't remember.
Enjoy your day.