problem with time machine backup really slow...

I am trying to back up with TIME MACHINE on my imac OS x 10.6.8 backup has been extremely slow (8 days later) only 467.67 GB of 702.72GB has backed up. It says it is backing up 1,644,032 items.

I have called WDcloud for help and they got me to hook the external directly to my mac which I have done said I have to seek the answers from apple regarding time machine.

I read somewhere to go to console and look for errors and I have done that and there are errors showing "fatal error Invalid bundle"

Not sure what to do now....do I abort the backup ?? How do I fix this so I can get my imac backed up. This was a first time back up.