When a float occurs on the same page as the start of a
supertabular you can expect unexpected results.
When the float was defined on the same page you might end up with
the first part of the supertabular on a page by its own.
You should not use the supertabular inside a
floating-environment such as table as this will result in
TEX trying to put the whole supertabular on one page.
In some instances you might still end up with overfull
\vbox messages. These instances are described in the
(documented version of) the style file itself.
Sometimes the last page of the supertabular contains just an
empty head an tail.