How is the GoFlex drive connected to the computer? Is it USB to the TC? That would be a very poor method to connect.
We need to work through the whole network to sort this one.
I suppose the starting point is any changes??
Has this setup worked ok and recently started this problem.. or a new setup that has never worked?
If the former then any changes that might be the cause?
TM has issues with TC in Lion particularly.. if you updated early. THere is a supplement.
If you run ML it also has issues but there are no fixes.
Describe the whole layout.. modem.. type of broadband??
How does the TC fit into the network?
Test with the TC removed and do you still experience issues?
Try with TC in different mode.
It is an existing setup that has worked before. The GoFlex is connected by ethernet to the Mac. The timecapsule is part of an extended wireless Airport network with an airport base station, one other airport to extend, and another timecapsule. The rest of my network works fine. This TC backs up my personal Mac, and the other TC backs up my business Mac. I had the same problem with mny other TC, but I reset it and now it works fine. I reset this TC, and it has the same problem. In Airport utility, the TC shows up as working fine. It shows up and shows green light. The backup starts, very slowly, then stops and gives me the error. I have now tried resetting it twice.
I would definitely get rid of any double hop wireless..
You might need to do some network rearrange but if the TC is not needed in the network directly you can use it by ethernet to the goflex..
Otherwise you need to totally redo the setup.. and make sure all the wireless is functioning correctly...
I would setup again using SMB names.. and fixed wireless channels.. if possible force the extend to use 5ghz if it is faster than 2.4ghz which means different names on that network.