Originally Posted by Toni Wilen
AOS libs:rexxsyslib.library includes huge amount of undocumented functions that AOS RexxMast requires and uses. (=it is not possible to mix different rexx system files)
I replaced aros rexxsyslib.library with AOS rexxsyslib, and rexxmast now launches properly(1); even arexx scripts DO work !
NOTE (1): sometimes upon being executed, rexxmast gives the following recoverable alert: "file handler closed more than once". But despite this error, rexxmast works subsequently, arexx scripts get executed.