I'm trying to create a C# library (DLL) that calls Mathematica 8 using the .NET/Link protocol. Specifically, I'm using it for things like FFTs, etc. Right now I'm using EvaluateToOutputForm and parsing the resulting string for doubles. Anytime I try using Evaluate() and GetDoubleArray(), it gives the error message (exception) that I'm trying to read from data of the wrong dimensionality. Even using Evaluate("2+2") and then GetInteger() fails with the error that the waiting data isn't an integer (basically).
The problem with EvaluateToOutputForm() is that the numbers I'm parsing from, say, Abs@Fourier[data] are wrong for non-trivial (e.g. fairly long) inputs. I can't tell what's going wrong. Can anyone here help me?