From what we can tell there's a uncommon condition on the network (seems to be about 1 in 10 clients), where some databases have became corrupt. Please check your logs for these messages:
--
2015-02-15 17:34:26 ERROR: ReadBlockFromDisk : Deserialize or I/O error - ReadCompactSize() : size too large
OR
2015-02-15 17:34:26 ERROR: ReadBlockFromDisk : Errors in block header
---
If you find entries like that delete ~/.darkcoin/blocks and chainstate, then resync from the bootstrap:
https://github.com/UdjinM6/darkcoin-bootstrap
Thanks 
How do you check your log in linux?
grep "ERROR" ~/.darkcoin/debug.log or you can monitor in real time using tail -F ~/.darkcoin/debug.log