It won't make DBC more like Pro - But it does give you full access to the API (most of which is unusable, as you can't find out the pointer to your code procedures what with them being interpreted, etc.).
However, there are some useful things in there..
For example, you have system shutdown commands, standard 'About Windows' boxes like the ones in Explorer when you click Help > About, printing capability, ability to multi-thread DarkBASIC - But you can't use it all, because DB doesn't even slightly support pointers, which the whole API is basically based around.
For that reason, it's better to suck up to a C++ programmer and get them to spend ten minutes making a 'wrapper' DLL for that DLL function - A DLL that automatically fills in all the difficult bits, as it were. It wouldn't take long to do one command.
How's my typing? Phone 0800-GO-TO-HELL