Hi Luís,
That's a rather unfamiliar error to me. Could you provide the code you use to produce the table and some portion of the contents of the table so I might reproduce the error?
Also, how many datapoints (rows) are in your table?
And did all three subjects provide data for both conditions?
Also, I believe your formula can be simplified to 'Angle ~ Condition + (Condition|Subject)'. Is there any particular reason you have it formulated the way you did?
Best,
Paul