Hi there!
First off, I've never tried the irda package that comes whith debian. I always get the source tarball, and it has always worked for me..
Have you tried to load the irda modules by hand? instead of hoping that irattach will do it for you?
The error you see in the syslog, is to my knowledge due to you trying to attach a tty that isn't and IR one, or one that doesn't exist.
Or maybe it is all because the modules aren't loaded.
If you are only interested in sir, you might try the following procedure:
insmod irda
insmod irtty
insmod ircomm
insmod ircomm-tty
irattach /dev/yourtty -s
and then it should work... at least that one has never failed for me.
/Johan