You need to set a higher difficulty for your workers. You're using the default of 64, which is far too low for anything less than one single GPU card. So your workers are probably being temporarily banned when blocks change, because your rentals send a flood of invalid shares since your difficulty is set so low.
There has been 5-15Gh of miners on ARCoin all night with the pool running fine.
Okey i try thanks

If i put 512 for 30mh/s is ok?
512 worker difficulty should be fine for 30Mh, 1024 may be better.
I created a new worker but my IP is banned i think
There's no IP banning - only temporary 60 second bans for your worker if you submit a lot of invalid shares at once (like using 64 difficulty with high hashrate miners on block changes). When you create a new worker, you have to wait 60 seconds for it to be sync'd to the pool servers.
If you're still having trouble, can you join our IRC channel? It may be easier to help you there. Its ##ipominer on Freenode IRC network.