Yeah, there is minimal error checking in the code since it was mainly for personal use. And I believe a level editor will fix the problem of the incorrect level number headers (though a set will play fine even when these are incorrect). Maybe I'll release an update to the code 
For Miika, here is an example of a ten-level input file (CCZone doesn't support tabs so just imagine the final space is a tab):
Josh-CCLP4.dat 60
IHNN1-CCLP4 mix.dat 41
Josh-CCLP4.dat 195
C1059-CCLP4.dat 60
IHNN1-CCLP4 mix.dat 17
Josh-CCLP4.dat 180
IHNN1-CCLP4 mix.dat 160
ZK4 submissions.dat 23
The Other 100 Tiles.dat 71
C1059-CCLP4.dat 34

For Miika, here is an example of a ten-level input file (CCZone doesn't support tabs so just imagine the final space is a tab):
Josh-CCLP4.dat 60
IHNN1-CCLP4 mix.dat 41
Josh-CCLP4.dat 195
C1059-CCLP4.dat 60
IHNN1-CCLP4 mix.dat 17
Josh-CCLP4.dat 180
IHNN1-CCLP4 mix.dat 160
ZK4 submissions.dat 23
The Other 100 Tiles.dat 71
C1059-CCLP4.dat 34
You should probably be playing CC2LP1.
Or go to the Chip's Challenge Wiki.
Or go to the Chip's Challenge Wiki.