Understand error message 1

I can only guess exactly what the error means.I have had it occurseveral times . Once in Sheetmetal Design, I tried to use the Walls Recognition and got the error. The part had 4 flanges, but one of the flanges was created with two different sketches on the same plane. I deleted the flanges one by one until I found the one that was causing the problem, then reconstructed the flange using one sketch. The error then went away. Another time I got the error when I had a sketch that did not contain any gormetry. I think it means a value that has been entered into some dialogue box creates a value or solution in the equation that is Infinity or nor relevant to the answer.Therefore the answer is invalid or "the handeler is null". Can you discribe the exact function you were in and what the circumstances were? Maybe we can try to repeat it and get a specific answer.