from the sed info page:
If you use `sed' at all, you will quite likely want to know these
[No addresses allowed.]
The `#' character begins a comment; the comment continues until
the next newline.
If you are concerned about portability, be aware that some
implementations of `sed' (which are not POSIX conformant) may only
support a single one-line comment, and then only when the very
first character of the script is a `#'.
I'm not sure what is meant by "[no address allowed]"
Perhaps if you added a space after the octothorpe character on line 9.
I copied and pasted your xclt.sed file and tried it out on a sample file which included
#... more lines here.
The program removed this range of lines without errors for me.
You might try deleting and re-entering line 8 in your script, in case there is a hidden white-space character at the end of line in your xclt.sed script.