Not sure if this is problem you encountered, Kevacoin's mainnet is not launched yet. For now, you have to pass the "-testnet" option to "kevacoin-qt.exe":

1. Open the command console (Click the search icon the task bar, type "cmd").
2. cd "Program Files\Kevacoin"
3. kevacoin-qt.exe -testnet
4. Wait for the wallet to sync.