I know you're posting in the z/OS forum, but on the UNIX command line, you can 'escape' spaces with a backslash immediately before the space:
PROD\ JCL2
Or you can enclose the file name/path in quotes:
"/SG01/fpl/ars/tmp/test.0.PROD JCL2.PROD JCL2"
Also, on your command line, you can enclose the Application Group name in quotes when using the -g parameter:
-g "PROD JCL2"
Maybe z/OS has something similar? Let us know if any of these options work -- and if not, paste in your entire arsload command/JCL so we can take a look at it.
-JD.