Winrar not working with NoCD exe files!

[thejoeflow]

Everytime recently that I've tried to replace an executable file from an installed PC game with a fixed exe that I downloaded from GCW I get the following error message:
! C:\Users\[username]\Desktop\dev.hppa.rar: Cannot create hppoa.exe
! Access is denied.
! C:\Users\[username]\Desktop\dev-hppa.rar: No files to extract

I am quite sure I have been abble to create a No CD fix for previous games, but I didn't have to go through winrar.
I would really love some help for this, thanks!
and if this isn't the right forum, please direct me to the correct place to post

and P.S that "hppoa.exe" is obviously for a specific game and not the same for all games I try to fix.