As in the Matlab interface, it is possible to detect errors with the functions NetSolveError[] and NetSolveErrorMsg[]. The first function returns an integer which is the error code of the last executed NetSolve function. NetSolveErrorMsg[] takes an error code as an input argument and returns a string describing the error.
With these two functions, it is possible to write Mathematica scripts that call NetSolve and handle all of the NetSolve errors at runtime.