From what I can try and ascertain using a pronunciation guide (not the IPA one) for Serbian and the Serbian spelling of his name, it is pronounced like...
- Dj... is pronounced as in "endure" or like in "bridge"
- o... is pronounced like "oh" but slightly swallowed. This is hard to describe; perhaps like in "score". Russians pronounce the vowel the same way.
- k... is pronounced like in "kick". No surprises there.
- vi... is pronounced starting with "vine" then the vowel is "week" (but kept short).
- c... in this case is pronounced like "church" but kept sharp.
The first syllable is certainly not "joke" (rhyming with the yellow part of the egg). Then again, I have gotten used to people mispronouncing names. I make it somewhat an objective to seek to pronounce people's names correctly; not everyone does, and it is probably unreasonable to hold them to the same standard.