MFE likes to add a prefix and suffix to my choice of name. I do not want that behaviour. When running a REXX to call other programs, dataset names are prefixed with the user ID and/or suffixed with the dasaset type. i.e EXEC or CLIST etc.

The problem can be solved by changing the QUOTES....

Assuming the program to be run is in  dsn=PROJECT.LIBRARY(PROGRAM)

"ex 'PROJECT.LIBRARY(PROGRAM)' "  will call the CLIST/REXX from the correct library.

The whole EXEC command should be double-quoted because it is an external (to REXX) command, not builtin. The dataset name member should be single quoted.