a bit of a late answer but this has to do with security.
I had the exact same problem and I added the Analyst role to my group and everything worked. I realized it was a security problem because the admin account could run the reports and my other users couldn't so I had to pick one of the reporting roles that allowed my users to run the reports. The Analyst role did it for me. Hope this helps.
Of course, if you change the outline and lost a dimension or something, then your report might still be searching for the old dimension and then you'll have this, or a similar error.