I couldn't get the script to work until I used Timothy Appnel's mt-rebuild utility to republish individual entries after they have been closed.
I run mt-rebuild from PHP with the language's system function:
system("$this->perl_path $this->mt_rebuild_path -mode="entry" -blog_id=$entry_blog_id -entry_id=$entry_id");
The $this->perl_path and $this->mt_rebuild_path references are object variables that hold the locations of Perl and mt-rebuild.
I found your entry while researching how to use XML-RPC to rebuild my posts. Calling mt-rebuild sounds even better. Thanks for the post!
For clarification, should pearl_path and mt_rebuild_path simply be replaced with the actual paths for my server?
Also, I believe the " in mode="entry" actually need to be ' so they don't conflict with the PHP enclosure.