Playing the arbitrage game can be really challenging for sure. I've seen the same with with Vericoin. A Chinese Exchange had it sitting at 5x the value on the USD exchange but it was nearly impossible to sign up and get it sent over there to profit from. Closed exchanges or wallets preventing movement in and out... barriers to prevent arbitrage and a solid explanation for why certain coins can be more valuable on one exchange over another
but such a big price difference between both exchanges is very unusual, but we´re at the beginning of the crypto boom, i hope, so when time comes the spread won´t be that big anymore, i hope ;)
This happens when markets are not liquid enough and when coins can be traded independently across centralized exchanges that determine their own pricing. Overtime we'll likely move towards decentralized exchanges that hopefully begin to reflect one single value for every crypto like it is with the Forex market. This space moves fast so it may not take too long until that happens.
We really are living in the super early stages of this space forming... like the early 1990's of the internet before it was common for every home to have a computer and access to the net through a dialup modem. Exciting times for sure and certainly far from mainstream