Have you checked to be sure that "Enable Cheat" is ticked in the SC menu for the file?
*Edit*
I highly suggest using the triple loader. It makes using cheats SO much easier. I have basically abandoned SC's menu in favor of YSMenu as my main loader. Much easier for cheats (usrcheat.dat can be used) and the speed is amazing.
*Edit*
I highly suggest using the triple loader. It makes using cheats SO much easier. I have basically abandoned SC's menu in favor of YSMenu as my main loader. Much easier for cheats (usrcheat.dat can be used) and the speed is amazing.