I am trying to set up a steem miner on Ubuntu 14 using latest code from https://github.com/steemit/steem. I've followed the following references:
1. https://steem.io/documentation/how-to-mine/
2. https://steemit.com/steemhelp/@joseph/mining-steem-for-dummies

However, I am only seeing the following on the console. Can someone provide pointers as to what I am missing?

```
next_block.validate_signee( witness.signing_key ): 
    {}
    th_a  database.cpp:2844 validate_block_header
rethrow
    {}
    th_a  database.cpp:2637 _apply_block
2583208ms th_a       application.cpp:448           handle_block         ] Error when pushing block:
10 assert_exception: Assert Exception
next_block.validate_signee( witness.signing_key ): 
    {}
    th_a  database.cpp:2844 validate_block_header
rethrow
    {}
    th_a  database.cpp:2637 _apply_block

    {"new_block":{"previous":"0000000000000000000000000000000000000000","timestamp":"2016-03-24T16:05:00","witness":"initminer","transaction_merkle_root":"0000000000000000000000000000000000000000","extensions":[],"witness_signature":"204f8ad56a8f5cf722a02b035a61b500aa59b9519b2c33c77a80c0a714680a5a5a7a340d909d19996613c5e4ae92146b9add8a7a663eef37d837ef881477313043","transactions":[]}}
    th_a  database.cpp:544 operator()
2583209ms th_a       fork_database.cpp:41          push_block           ] Pushing block to fork database that failed to link: 00000002ed04e3c3def0238f693931ee7eebbdf1, 2
2583209ms th_a       fork_database.cpp:42          push_block           ] Head: 1, 0000000109833ce528d5bbfb3f6225b39ee10086
2583209ms th_a       application.cpp:445           handle_block         ] Error when pushing block:
3080000 unlinkable_block_exception: unlinkable block
block does not link to known chain
    {}
    th_a  fork_database.cpp:62 _push_block

    {"new_block":{"previous":"0000000109833ce528d5bbfb3f6225b39ee10086","timestamp":"2016-03-24T16:05:36","witness":"initminer","transaction_merkle_root":"0000000000000000000000000000000000000000","extensions":[],"witness_signature":"1f3e85ab301a600f391f11e859240f090a9404f8ebf0bf98df58eb17f455156e2d16e1dcfc621acb3a7acbedc86b6d2560fdd87ce5709e80fa333a2bbb92966df3","transactions":[]}}
    th_a  database.cpp:544 operator()
2583210ms th_a       fork_database.cpp:41          push_block           ] Pushing block to fork database that failed to link: 000000035b094a812646289c622dba0ba67d1ffe, 3
2583210ms th_a       fork_database.cpp:42          push_block           ] Head: 1, 0000000109833ce528d5bbfb3f6225b39ee10086
2583210ms th_a       application.cpp:445           handle_block         ] Error when pushing block:
3080000 unlinkable_block_exception: unlinkable block
block does not link to known chain
    {}
    th_a  fork_database.cpp:62 _push_block

```