### "Missing number, treated as zero"

In general, this means you've tried to assign something to a count, dimension or skip register that isn't (in TeX's view of things) a number. Usually the problem will become clear using the ordinary techniques of examining errors.

Two LaTeX-specific errors are commonly aired on the newsgroups.

The first arises from a misconfiguration in a system that has been upgraded from LaTeX 2.09: the document uses `\usepackage{times}`, and the error appears at `\begin{document}`: the likely cause is lurking files that remain from the LaTeX 2.09 version of the times package. The times package in psnfss is a very simple beast, but the LaTeX 2.09 version is quite complicated, and loads another package: this is clear in the log if you have been "bitten" this way. The resolution is to clear out all the old PostScript-related packages, and then to install psnfss.

The second arises from attempting to use an example describe in The LaTeX Companion, and is exemplified by the following error text:

    ! Missing number, treated as zero.
    <to be read again>
                       \relax
    l.21 \begin{Ventry}{Return values}

The problem arises because the Companion's examples always assume that the calc package is loaded: this fact is mentioned in the book, but often not noticed. The remedy is to load the calc package in any document using such examples from the Companion.

`calc.sty`
  Distributed as part of macros/latex/required/tools.tar.gz
`The psnfss bundle`
  macros/latex/required/psnfss.tar.gz