The problem is somewhere with the spells.2da and the dialog.tlk file. As I mentionned above, the two files do not correspond and I suspect you dropped one of them in the wrong game folder (k1 instead of k2 or vice versa).
Kotor 2 original dialog.tlk has about 120 000 entires while in K1 it has only about 50K entries. The error message you are getting says that your spells.2da file is looking for entry no. 124 483 in spells.2da but can only find 50K entries.
That makes only 4 files to check, not 1880
You can open them with Kotor tool.
Edit: or for a quick solution, try removing spells.2da from your k1 and k2 override folders while you edit with KSE. If it works, then the spells.2da file was the wrong one. If it doesn't work, then the problem is with the dialog.tlk file.