yEnc32 - GUI yEncoder/yDecoder

Also, I need to add that if I right click, then chose either to encode or
to decode with yenc32, it says,
"Could not execute yenc32 to decode/encode this file"

Nothing seems to fix this either.

I have experienced the same problem just a few minutes ago. Firstly, I
installed yEnc32 v1.0.8 under Windows XP Service Pack 2 and then
uninstalled it using the add/remove software tool from Windows' setup menu.
After that I wanted to install it again running the same downloaded .exe,
but got the error you described.

The details of the setup window display the following:
Output folder: C:\Program Files\yEnc32
Extract: yEnc32.exe
Extract: yEnc32.exe.manifest
Can't write: C:\Program Files\yEnc32\yEnc32shell.dll

When I tried again I got the same error message. Note that this problem
occurs when you remove a previously installed copy of yEnc32 1.0.8 and try
to install it again, the first time no error messages were displayed.
Ignoring this error and continuing the process seem to work fine, though.