I got some strange "underfull \vbox (badness 10000) detected at line ..." warnings, obviously at each of my "longtable"s. Is there a way to fix them (I actually don't see the cause) or do I have to ignore them?

Minimal working example (PdfLaTeX tells these warnings triply for each run on compiling with `longtable [2000/10/22 v4.10 Multi-page Table package (DPC)]`; each `\demounderfullvbox` might be replaced by the full example code or the source may be reduced to one `longtable`, what doesn't change behavior):

```
\documentclass[english,11pt,a4paper]{article}
\usepackage{longtable}

\newcommand{\demounderfullvbox}{%
    \begin{longtable}{|l|p{2in}|}
    %
    \endfirsthead
    %
    \hline\multicolumn{2}{|l|}{\textsl{\ldots continued from previous page}}\\*
    \endhead
    %
    \multicolumn{2}{|l|}{\textsl{will be continued on next page\ldots}}\\*
    \hline
    \endfoot
    %
    \hline
    \endlastfoot
    %
    \hline%
    aa: & 4711\\
    \hline%
    aaa: & 2\\
    \hline%
    aaaa: & 4711-2\\
    \end{longtable}
}

\begin{document}
\newpage
%
\demounderfullvbox
\demounderfullvbox
\demounderfullvbox

\end{document}

```

If `tabular` is used instead of `longtable`, no warnings occur, but that doesn't solve the problem, as much more rows can be placed in the tables.

Removing the trailing `\\` in the `aaaa:` line has no effect either.

The "underfull \vbox" warnings seem to specify a source line that looks ok to me (this is more clearly when `\demounderfullvbox` is replaced by the example code), think the warning is provocated on computation of first LTchunk?

Thanks for help and suggestions in advance!