To use Serenji on a Caché system you first have to load some routines. Apart from one named %ZDEBUG these routines all have names starting with "%Serenj".
Prior to Caché 5.1 and Ensemble 4.0 these routines could be easily loaded into %SYS. This operation is described in Serenji's online help.
Caché 5.1 and Ensemble 4.0 have new rules about where %-routines are by default retrieved from. These locate %Serenj* routines in the CACHELIB database, and that database is normally read-only.