If you have a script, say script.py, which is not executable by itself (it has no executable flag), and you are calling from directory /dir/of/script:

$ jman -l submit python script.py

The submitted job will be

$ jman ls -l
[...] '/dir/of/script/python' 'script.py' 

instead of

[...] 'python' '/dir/of/script/script.py'

When you specify the full path of the executable, this will work:

$ jman -l submit /usr/bin/python script.py
$ jman ls -l
[...] '/usr/bin/python' 'script.py'

but the path to the script is lost.

Hence, currently there is no way of running a non-executable script. I remember that jman had an option for the executable once before, but for some reason I cannot find this anymore. Maybe, this option should be revived.