this error is related to input data (in ArcSWAT) or parameters (in SWAT-CUP). This error is very common, to resolve it: If you're facing this error in ArcSWAT, check your input data and in SWAT-CUP, check your input parameters (in particular, range of parameters).
Usually, this error occurs due to some error in input data in arcswat or input parameters in swatcup, particularly the range and qualifier (a, r or v). So check them out.
It might be also due to an error during copyying of files from swat to swatcup when you setup the project which probably ended up with some corrupt files so try to setup the project again.
Go through these links for further information:
https://groups.google.com/forum/m/#!topic/swat-cup/WtekXjek1Ug