There are several references to the error in discussion if you look at the more like this on the right ..
This one has some answers.. basically option click on the Time Machine icon and use the verfiy backups.
https://discussions.apple.com/thread/3123920?answerId=17748380022#17748380022
I don't think Pondini lists that particular error but it is caused by a combo of issues.
He has a few answers listed in the post above.
You have listed the OS is 10.7.4 Is this correct??
There was a supplement to 10.7.5 to fix some serious TM issues.
http://support.apple.com/kb/DL1599
Then just follow some of the instructions in the pondini trouble shooting.
If the backups are corrupted you might need to erase and start again.. this is not unusual with wireless connection.