1. Im pretty sure you specify dark basic pro's main directory (usually C:/Program Files/The Game Creators/Dark Basic Pro).
2. No they havent been fixed yet, and chances are wont, since the default IDE's source doesnt belong to TGC. Id recommend getting Code Surge IDE.
3. Sproadic Crashes I havent experienced but whenever you're using the default IDE, its always a good idea to a) do save all's frequently, b) copy your updated code into a notepad text file, and c) copy all of the code in your project before opening up a new project.
4. The main problems with saving are that sometimes, even if you've save all'ed and all that good stuff, it just doesnt want to save, and all your code is gone. I use the default IDE a lot, and Ive found this is the best way to fix all of this:
a) Create a new project
b) Write a comment on the first line, like `Game Code or something.
c) Do file > save project as, file > save source as, then go to the project manager and save the executable in wherever your project is, then do a file > save all. Now re-open this project (file > open recent), if the comment line is still there, you're good to go, and you can just use 1 save all whenever you feel like it from there on in to save your code, and it'll save properly. If its not there, you did something wrong probably.
d) Double compiling is bad. Dont do it, and you wont get into problems. Double compiling is basically compiling your project / running it, then compiling it again and running it while the original compilation is running. This forces Dark Basic to create a temporary exe file in the windows temp folder, and it then saves your project path to that temp folder. Now whenever you save your code will be saved in the temp folder and deleted soon after. Instead of double compiling, just have Windows Explorer open with your game folder open, and click the game executable if you want another instance of your game running (maybe for multiplayer testing).
To fix the problem in d, you'll have to copy all the code in your project, reopen the project, replace the code in the project with your new code, and redo the steps in part c.
A lot of hassle... Id recommend just getting Code Surge. Either way you should still always make backs ups of your code.