The string was meant to be used with ASM8 but not with CW. Obviously it won't work with CW.
The 2nd suggestion is to use a generic script language to do this work for you as part of the build process, i.e., one extra step in your makefile. (If you don't use makefiles then simply run it right before you assemble your code whichever way you normally do.)
I choose Lua for these tasks as it is one such script language which combines programming simplicity and sophistication, in my view -- but you could use whatever other scripting language you're comfortable with assuming it provides some method to get the system clock as a string.
So, the script I gave in the earlier reply is for Lua. Assuming lua.exe is somewhere in your path (no installation needed, just place the lua.exe somewhere in your path), and you have named the script 'generate_datetime.lua' you would have to give this command (preferably from the console):
lua generate_datetime.lua
This should create the file today.inc (in my example) in the same directory you were when you ran the above command. So, you probably want to run it from inside the project's directory.
The produced file will contain the needed assembly language code that will embed the date/time stamp in your app.
Every time the script is run the file will be updated with the current date/time stamp. Then just assemble your program as usual.
To have the date/time stamp appear in your code, at the relevant point in your source you have to include the generated file, like so:
#include today.inc
Simple?