GNU sed version 4.2.1 bug?

[Joshua Schriver]

I have a line in a script:

                sed -ire 's:([^\\]*)\\(.*):<\1 >\n\2\n</\1 >:g' tmpfile

That gives the following error:
sed: -e expression #1, char 36: invalid reference \2 on `s' command's RHS

When I'm using the -I option.
Changing the line to the following works without errors:
                sed -re 's:([^\\]*)\\(.*):<\1 >\n\2\n</\1 >:g'  tmpfile > tfile2

Why would the in-place option make or break the replacement expression?

Joshua Schriver
Electrical Engineer
Pitney Bowes - Document Messaging Technologies
(203) 739-2296