In order to be able to evaluate the Challenge-III levels, you will have to edit your ltEvaluator.ini file.
Change the number in the Items line and add the new line 3=Challenge-III
Of course, you also change the line number (3,4,5,6 to 4,5,6,7)
(look at the following example) -----   Do not change the other lines.

Of course you do the same for other levels files like the new Sokoban-II file.

But best of all, click here to download the already modified ltEvaluator.ini file.

BEFORE
[Config]
Name=XXXX
File=XXXXXXXXXXXXXXXXXXXXXX
Language=Us
(Us or Fr)

[Level Files]
Items=6
1=Challenge-I
2=Challenge-II
3=Lasertank
4=Sokoban-I
5=Sokoban-II
6=Special-I

AFTER
[Config]
Name=XXXX
File=XXXXXXXXXXXXXXXXXXXXXX
Language=Us
(Us or Fr)

[Level Files]
Items=9
1=Challenge-I
2=Challenge-II
3=Challenge-III
4=Challenge-IV
5=Gary-I
6=Lasertank
7=Sokoban-I
8=Beginner-I
9=Special-I