Err 01 - 5D and Sigma 24-60

So, I have a Sigma 24-60 f2.8 and I recently picked up a 5D. For the first 2 weeks everything seemed to work fine but over the last 2 or 3 weeks, every time i put the lens on, I get about 10 shots and then I get an Err 01 code. I searched on the code and did what the Canon site said to clean the contacts, but still no luck. I'm wondering if this is a lens issue or a body issue. At the same time, my Canon 50 f1.8 has never given me this issue. This leads me to believe it's the Sigma lens and not the body. Has this happened for anyone else and was it fixable?

Thanks.

I have never had an error message with the 24-60 on my 5D. (excellent lens btw)
If cleaning the contacts had no effect and it does not happen with other lenses, I suspect that their may be a faulty chip on 24-60 and either replace the lens or get it repaired.
I had a faulty chip on a Sigma 20/1.8 some years ago and Sigma replaced the chip with no quibble and it functions perfectly ever since.

Thanks, I guess I'll just have to send it in for service. Strange, cause I just purchased it earlier this year.