why executable file 'readin' not found but it is there

[joe at actionline.com]

In my /home/joe/bin directory, I have hundreds of
shell scripts that I use for various utilities.

Recently, thanks to advice from Matt Graham, I added these
lines to .bashrc which got most of those utilities to work:

export PATH=/home/joe/path:$PATH

However, one of the files in /home/joe/bin is a proprietary
binary file named 'readin' that functions like a "hot key"

It works fine on my other Linux boxes, but since I copied my
entire 'bin' directory onto another Linux machine, I can't
get 'readin' to work on this machine.

In fact, it cannot even be "found" even though it is certainly
there in /home/joe/bin ... but when I type readin at the command
line, I get this message:

joe at drifter:~/bin$ /home/joe/bin/readin
bash: /home/joe/bin/readin: No such file or directory

Hope someone can explain why 'readin' is not found
when it is actually there.