revCopy file in OSX doesn't work

[Sieg Lindstrom]

I've searched the archives and see this problem has been discussed before,
but none of the advice therein helped me. Any idea why this code works for
me in OSX...

if there is a file "1-meet data/ABC affils" then put "found"

But the following does not?

on mouseUp
-- "1-meet data" is the folder containing the file I'd like to copy.
-- "2-processed meet data" is the folder I'd like to copy to.
--Both folders are in the defaultFolder.
--"ABC affils" is the name of a .txt file

    revCopyFile "1-meet data/ABC affils", "2-processed meet data"
  
end mouseUp

The file does not get copied and the result is "execution error."

The fact that the first code fragment works suggests I have the file path
right. But revCopy File disagrees.

Thanks in advance for any solutions.

SL