"node has to be up to date?"
Check that when you run chaincoin-cli getinfo you get "version" : 90302 (that is the latest).
"POS score should be zero"
Check that when you run chaincoin-cli masternodelist pose IPADDRESS (where IPADDRESS is the ip address of your masternode) you get a result of 0.
I just set up 2 Masternodes and run them from my desktop wallet. They have been running for 5 days straight without receiving any rewards. I am running the latest 90302 version and "chaincoin-cli masternodelist pose IPADDRESS" returns a result of 0. The debug log does show a lot of "MasternodePOS::mnse - MasternodeB ranking is too low" errors. Is there any guide to troubleshoot problems with masternodes? I had faith in Chaincoin when I decided to start running Masternodes, but I am fairly disappointed with the loss in initial investment (bought in at $0.20), and lack of rewards.