No, I don't know why at all, but I had same problem at 0.3 version.
I checked TFS 1.2 sources.
If you can see, in your const.h, there are already empty effects, so you don't have to add new one in tibia.dat:
// 77-157 are empty
So just do like I said, register effect number 77:
CONST_ME_EMPTY =...