I've checked data.ini already, and it's exactly as it is in the FAQ.. but here it is anyway.
[Data]
0=heRO.grf
1=sdata.grf
2=data.grf
I've ran setup.exe and.. I don't think that's the issue.. o_o' The setup works fine.. If it helps any, attempting to run Ragnarok and Sakray, it also gives me a similar error with a slightly different error report. If you'd also like those, I'll post those codes as well.
As for when this error comes up, yes. As soon as it starts up. It won't even get to the login screen. ._.;