ID:1968122
 
(See the best response by Mr_Goober.)
Code:
#define MOB_SAVE  "\[save] Sword Ascension Online/"

mob
verb
Client_Save()
var/savefile/F = new("[MOB_SAVE][src.ckey].dat")
F["mob"] << src
F["x"] << src.x
F["y"] << src.y
F["z"] << src.z
src << "You've saved your character!"
return


Problem description:
Apparently MOB_SAVE isn't defined.

error: MOB_SAVE: undefined var

Best response
When using #defines, always make sure that they exist at the very top of the program. Text macros won't be known to the compiler before they are defined unlike usual DM code. It's usually easy to just write a file like "_defines.dm" that gets pushed to the top of the code compilation in the DME because of its alphabetical order.

You can also write your definitions directly into the DME if you so wish to.
Well that's lame. Thanks for the help.