I followed your link and according to the Patch that is closed it has been accepted i.e. included in the standard rockbox build and should be found in the 3.1 release
Misreading it you are. The patch to Rockbox which creates the audioscrobbler log has long been accepted. The link to the perl script for rockbscrobbler is long gone from mysticriver it appears.
Mind you, Stephan, that rockscrobbler does not support the 1.2 protocol, so you must
submit tracks in order. This means if you listen to a few tracks on the way to work with Rockbox, listen on your PC when in the office, listen with Rockbox on the way home, those tracks you logged on the way to work will not get submitted (assuming a submission by the office PC.)
QTscrobbler does not have this issue - so you may not be aware that most other submitting programs do.http://www.rockbox.org/twiki/bin/view/Main/LastFMLog