Mind reading the FAQ section of the website ? That should explain all your queries.After reaching a minimum payout limit ,you will be asked for the bitcoin address to which the coins are directly sent from the website .So not sending enough coins to the block chain does make sense when your payout amounts are lower than the tx fees.
I have already read the faq page. It says that :Quote
Sponsors set payouts per 100 Twitter followers. If you have less than 100 Twitter followers the reward for retweeting may be too low to be sent to the blockchain.
I already have 1500+ followers on my twitter account, but still receive this error.Also, I get this error when i retweet any post and not when i withdraw, and the balance too remains zero .
