Paul Manafort was the campaign advisor for ex-President of Ukraine, Viktor Yanukovich. During Viktor Yanukovich second presidential run he hired Paul Manafort as his campaign advisor. As much a Donald Trump tries to downplay Manafort's involvement with the Ukraine anyone who is familiar with Viktor Yanukovich and his downfall will remember his often present advisor.
Yes, Paul Manafort absolutely has professional and personal ties to Ukraine. As described by multiple news outlets, Paul Manafort, Donald Trump's campaign manager, was previously an advisor for the Ukrainian presidential campaign of Viktor Yanukovych. He is now under investigation from the Ukrainian government's National Anti-Corruption Bureau which alleges that Manafort received large cash payments from a pro-Russian political party.
I don't know for certain, but it definitely seems like Manafort and others Drump campaign people have some level of involvement with factions in the Ukraine which have ties to Putin. Manafort has been named in a probe to examine the "secret" ledger and the money trail. There's certainly enough that it looks pretty fishy.
There is no evidence to support the rumors that Paul Manafort has received secret payments from Ukraine. He does not have a lot of foreign policy experience and has made some controversial statements, but much of the accusations being made against him are just politically motivated and not founded in any truth.