You shold be able to mine till block 21600 "Total block number : 21600"...

I'check the pool now ...

 General Statistics
Pool Hash Rate   0.000 MH/s
Pool Efficiency   99.79%
Current Active Workers   0
Current Difficulty   0.39718182
Est. Next Difficulty   0.09850195 (Change in 1 Blocks)
Est. Avg. Time per Round (Network)   8 minutes 3 seconds
Est. Avg. Time per Round (Pool)   zero seconds
Est. Shares this Round   26,030 (done: 3336.05%)
Next Network Block   19,804    (Current:19,803)
Last Block Found   19,710
Time Since Last Block   15 hours 8 minutes 51 seconds

And the block chain....

http://vps81017.ovh.net:2750/chain/0NECoin

Block   Approx. Time   Transactions   Value Out   Difficulty   Outstanding   Average Age   Chain Age   % CoinDD
19803   2014-07-29 21:29:55   1   0.0000301   0.397   0.94588021   9.89906   66.0208   67.6837%
19802   2014-07-29 21:29:48   1   0.0000301   0.297   0.94585011   9.89929   66.0207   67.6839%
19801   2014-07-29 21:29:43   1   0.0000301   0.3   0.94582001   9.89956   66.0206   67.684%
19800   2014-07-29 21:27:42   1   0.0000301   0.408   0.94578991   9.89847   66.0192   67.6871%
19799   2014-07-29 21:24:59   1   0.0000301   0.527   0.94575981   9.8969   66.0173   67.6913%
19798   2014-07-29 21:22:24   1   0.0000301   0.685   0.94572971   9.89542   66.0156   67.6953%

It seems all right.... Maybe it's just a problem on pool side.

Maybe it's better if you ask to the dev!