>Is the X-Windows LINUX client known to be full featured?  Reliable?

Remarkably so for such an ad hoc package.  I've had no errors reported
by the satisfied Linux users at my site, who are delighted to have
this package to back up their systems.  The Xwindows portion works
perfectly for them.

Unfortunately, Xwindows errors are notorious for being obscure and
telling you nothing about what's actually wrong.  The best approach
may be to search the web on key elements of the messages, in
conjunction with an Xwindows book.  I can say that GC refers to...

GC                                      Graphics Contexts.  Most attributes of
                                        graphic operations are stored in
                                        GCs. These include line width, line
                                        style, plane mask, foreground,
                                        background, tile, stipple, clipping
                                        region, end style, join style, etc.
                                        Graphics operations use these values to
                                        determine the actual drawing operation.
  Richard Sims, BU