There is a reason its disabled...
When you load that checkpoint you will probably get stucked to the ground.
But if you wanna edit it anyway:
lines 258-261:
Code:
if(entity_get_int(id,EV_INT_flags)&FL_DUCKING) {
client_print(id,print_chat,"[ProKreedz] You can not create a checkpoint while ducking")
return PLUGIN_HANDLED
}
Delete them.