You often can't put the replacement cam in the main directory as the directory is often read only. The var/bin directory should be used as it has no such restrictions and should be searched by the system first and override main dir. Leave the original incubus cam in place. I always rename current incubuscamd.sh4 in var/bin to eg incubuscamd.sh4v92 then ftp new version 0.93 to var/bin and change file attribute of the incubuscamd.sh4 to 755. Then if using DGS image press green button to restart cam.
I understand from your comment, first i should be rename the sh492 in data(current version)then copy sh493 in var/bin. did i understand your mean properly?
last question, is incubus 93 better than 92 version to replacement?