I finally got the underpinnings of my project working, the whole stack of apps and components all connected together and (minimally) running. I don't feel like quite such a dolt tonight, though it may be a while before I feel comfortable developing apps for UNIX-Linux systems. One has to start somewhere.
In this case, my frustration was caused by problems in not just one but two of the four layers, the Tcl/Tk library from ActiveState and the PAGE visual form design tool. Unsurprisingly there were no actual errors in ActiveState Tcl/Tk 8.6, only a misunderstanding on my part as to how it was to be hooked up to the PAGE tool. And PAGE worked fine once I ran a configuration script that determined for PAGE just where it should look for its underpinnings. To complicate matters, versions of Python built in the past few years all have an earlier version of Tcl/Tk built in to the runtime/development environment, so that PAGE was attempting to talk to Tcl/Tk 8.5.11 rather than 8.6 . Both errors on my part were educational; I learned still more about some very basic *nix operations in chasing down the problems. I'm afraid I have a lot more very basic things to learn.
One frustration to a newbie like myself is that in the *nix world, hardly anyone writing documentation... man pages, forum posts, introductory articles, whatever... feels a need to explain one single fact more than the minimal amount necessary for an experienced person (user or programmer) to use the software described. One painfully common fault is describing the changes one must make to a configuration file without ever mentioning where to find the file. Fortunately I found a good search tool; I'd have been unbearably taxed by doing all the searching in something as slow at searching as, say, Nautilus. This is a marked difference from the Windows world, where the doc writers' assumption is typically that the consumer of documentation is an utter idiot.
Onward into the fray...