Translation:I am busy for a little while.
"(something)間に" marks a specific timeframe in which something occurs. For example: 5日間に = "within 5 days" (and no more than that), or 留守の間に = "while I am/was out" (thus before I return(ed)). This sentence on the other hand leaves it somewhat vague how long 'a little while' actually is.
It is a awkward translation, ceo to secretary: I'm going to be rather busy for a bit.. Hold my calls. I'm a bit busy right now.. A little busy.... For a time.. For a short time.. For quite some time.. For quite awhile? I dunno quite how i might improve it... How long is awhile? A little bit of time.. A brief time... Some time.. A little busy so.. Maybe, "I'm a little busy at the moment.? Hmm