Dear giedi I had a protracted support call with Microsoft on the 'the Requested value '()1' was not found' issue. At the end (for me) it was (and still is) a local computer environment problem. I don't know what, but I cannot use PowerBI on my Dell laptop. Something on the machine (and I don't have the inclination nor the energy to look for the problem) as I used several tools with no success, causes it. I simply had to use another machine for PowerBI.
I never rebuilt the Laptop, again for the reasons cited above, but that would be the only next step to try and cure the problem by broad stroke. In my opinion, the problem is not with PowerBI and the error is so unusual that Microsoft has not coded to handle the error, because you can simply not isolate it by error message to find the cause. giedi sorry I don't have better news.