Incorrect Object Visibility

G'Day

A quick search on the title of this post returns no corresponding
hits. This is part of the error reported and corrected by a drawing
audit. "Incorrect object visibility 1. Object visibility set to 0."

I threw together a Vlisp utility employing the ObjectDBX interface. It
is used to import a layout and all its contents from the source DBX
document. This works fine, save for the layout which occupies first
position in the source DBX. Once imported, I attempt to turn on the
viewport that came along with the layout contents. Once turned on, all
other objects 'disappear' save for the outline of the viewport. A
regen restores the picture, but Acad is now unstable and will freeze
and/or crash shortly thereafter.

Performing an audit immediately after importing the DBX contents and
before attempting to turn on the viewport produces the audit results
mentioned above. However, even after the audit, the same outcome
follows from turning the viewport on. Acad is unstable.

All other layouts imported from the source DBX, occupying layout
positions 2, 3 and so on, produce none of the effects that the import
of layout 1 will. Changing the order in which layouts are imported
makes no difference. Even after creating a couple of default layouts
and moving them into first and second positions in the source DBX does
not relieve the problem. Nor does the problem appear to be confined to
this one source DBX document. The same happens with another.

At the moment I'm quite perplexed. Anyone ever encounter an "Incorrect
object visibility" error before?

Brian.