The problem is not with the Position function, but rather with the Middle function; the third parameter of Middle gives the length of the string to be returned not the position of the end of the string
start = Position ( index ; "." ; 1 ; 1 ) + 1 ;
end = Position ( index ; "." ; 1 ; 2 ) ;
length = end - start
Middle ( index ; start ; length )
should give you what you want
that's it. Now all's right with my FileMaker-world again.
Thanks a lot for clearing this up for me.