**EDIT:** Looks like you're using minerd (which to my understanding doesn't have stratum support.)  Slush's pool requires it [(the FAQ seems to mention this briefly)](https://mining.bitcoin.cz/faq/).

Suggestion: Try using one of the miners listed in the FAQ.


Old post: It looks like new blocks are being generated faster than your machine can complete a single unit of work.

[Perhaps you could provide us with a more complete log file?](http://pastebin.com/)