I am trying to modify calender.exe...but the phone won't let me...

[ManuTouch]

I am running Manila 2d, or Touch Flo 2d or whatever the hell it's called now, anyhow, I am trying to follow these instructions....

To launch another PIM from TouchFlo 2d from the home tab:

1. Download VJBrisk app (one of Vijay555 tools).

2. Rename VJBrisk to Calendar.exe and the shortcut to your PIM app to (ex. agendaone.lnk) to VJTarget.lnk.

3. Place these two files into \Windows folder.

That's all fine and dandy, but windows mobile won't allow me to overwrite the old calendar file with the new one....how am I supposed to do this?????