Am trying to design a Data Flow Diagram for a system using Visual Paradigm Community Edition on Ubuntu 14.04 but can't seem to find Data Flow Diagram in the list of diagrams, any clue why since according to visual paradigm website, there should be a data flow diagram in the list of diagrams??
Data Flow Diagram is available in the Modeler (and any higher) Edition of Visual Paradigm. Since you are using the Community Edition, which is an edition below the Modeler Edition, you cannot create Data Flow Diagram there.
If you meant to evaluate this feature, try with their evaluation version instead. You can download it from their download page: https://www.visual-paradigm.com/download/