JFFNMS version 0.9.2 was released today both as an upstream tar.gz file and a new Debian package. This version fixes some bugs including making sure it works with PHP5.4.
The biggest change in PHP 5.4 is that you can no longer call by reference. Previously you could call a function like myfunc(&blah); which would send a pointer to blah and not the item itself. Now the function definition needs to define what it wants rather than change it each time.