development_genesis.json

{
    "nonce": "0x0000000000000042",
    "difficulty": "0x40000",
    "alloc": {
            "bbbbbaaaaa82db86a35502193b4c6ee9a76ebe8f": {
            "balance": "10015200000000000000000"
        }
    },
    "mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "coinbase": "0x0000000000000000000000000000000000000000",
    "timestamp": "0x00",
    "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "extraData": "0x",
    "gasLimit": "0x4c4b40"
}

The comma on the end of line 7 causes it to fail like this:

Fatal: invalid character '}' looking for beginning of object key string

Removing that comma allows it to be loaded.

Tip to stop anyone wasting time like I just did: You need enough memory to mine. If you never seem to find any blocks on your local testnet despite having the difficulty right down low, try closing some Chrome tabs...

Same issue

Fatal: invalid character '}' looking for beginning of object key string

Kindly guide how to sort this issue. System is 16GB RAM with i7 + ATI Radeon 8k series. Mining should not be a issue.

Seems like some thing wrong with genesis file

I am having the same issue
WARNING: No etherbase set and no accounts found as default
...
Fatal: invalid character '}' looking for beginning of object key string
Fatal: invalid character '}' looking for beginning of object key string
edit:

okay so this issue is caused by an extra comma at line 7. Removing it solved this particular issue.

Weird that it never errored for me, made the changes :)