"A loop was found in the data source view at the 'dbo_....' table"

Argh! I was just adding and refactoring a few dimensions, and when I process one of my partitions, I get this error:

"A loop was found in the data source view at the 'dbo_Account' table"

What does this mean, and any ideas on where I should debug to repair it? All the SQL queries in my DSVs look sound...Ok. I went back and looked at the 2 dimensions I added - they were referenced. They were set to be materialized. I changed them so that they were no longer materialized. Everything works great now. I have no idea why.

The only bad part is that I feel like I wasted 3 hours.