downloaded Data-Flow-1.02.tar.gz and followed makefile.pl followed by dmake install for both the modules

That should have worked. One would normally run 'dmake test' (to check that the module tests correctly) before running 'dmake install' but, as best I can tell, what you did should have resulted in a successful install - with no need to 'use lib'.

Is the .PL extension associated with ActiveStatePerl 5.16 ?
If it's associated with another perl installation, then 'dmake install' would have installed the modules into that "other" perl installation.
When you run 'dmake install', it will tell you where it's installing the files - make sure they're going where you expect.

Cheers,
Rob