Tie machine is attemptint to make backups at intervals of about 10 minutes and getting itself into a right knot. The backups themselves take only a matter of minutes.
Being backed up to an external hard dricve over wifi.
Tonight for example
Welcome to the Apple Support Communities
First, reset Time Machine > http://pondini.org/TM/A4.html
If it doesn't work, use TimeMachineEditor to set up the intervals manually
Retrieving data ...