hello... examples: "what about him," is " iss(next) ke baare mein kya hota hai?" and "about that(problem...) i can't do anything" is " iss baare mein main kuch kar sakta nahi hoon"......i think

I wouldn't say they have the same meaning or if one is a short form of another. Let me give you an example - If I ask you a question "आप किसके बारे में बात कर रहे हैं" Then you can say " मै इसके बारे में बात कर रहा हूॅं" But you can't say "मै इस बारे में बात कर रहा हूॅं" . And if I ask "आप किस बारे में बात कर रहे हैं", Then you can say "मै इस बारे में बात कर रहा हूॅं " But you can't say " मै इसके बारे में बात कर रहा हूॅं". Adding the word 'के' specifies we are referring to a noun.

इस बारे में is just a short form for इसके बारे में , and the former is informal in a way.

Same meaning

Almost both are same meaning.