MiKTeX, TeXnicCenter and “cancel” package - errors [closed]

Question

EDIT2: I answered it below. I had duplicate of my cancel.sty where my .tex file was. That made some troubles (obviously).

EDIT:

\documentclass[a4paper,11pt]{article}
\usepackage[croatian]{babel}
\usepackage{cancel}
\begin{document}
\mbox{}\cancel{a}
\end{document}

I went to MiKTeX Package Manager, found "cancel" package, right click -> Install. Refreshed FNDB. Opened TeXnicCenter, wrote that code and tried to render it. I got 16 errors. Why (for me "normal" LaTeX, packages like amsmath are working and I'm able it to render it just fine, but now I need some additional functionality like this strikethrough in cancel package)?

MiKTeX 2.9
TeXnicCenter 1.0 RC1
- rendered via Sumatra PDF

Answer 1

Don't use \cancel on the very first word. It works for me, if I begin with a character or just \mbox:

\documentclass[a4paper,11pt]{article}
\usepackage[croatian]{babel}
\usepackage{cancel}
\begin{document}
\mbox{}\cancel{a}
\end{document}

If I use \cancel at the beginning of a paragraph, as in your example, I can confirm there's an error:

! You can't use `\/' in vertical mode.
\@cancel ...ht \unitlength \p@ \canc@thinlines {\/
                                                  \raise \dimen@ \hbox {\ooa...
l.7 \cancel{a}

Answer 2

The cancel package description states:

A package to draw diagonal lines ("cancelling" a term) and arrows with limits (cancelling a term "to a value") through parts of maths formulae.

As such using $\cancel{a}$ should work. For this to work after installing the cancel package, you need to update your FNDB (filename database) first (See How do I refresh the file name database?).

This may be an isolated case since the use of \cancel{a} as the first element in a document (or paragraph) is unlikely in general and therefore particular to this test case. Prepending \cancel with anything is sufficient to remove the error.

Answer 3

Ok, the thing was I had copy of my cancel.sty on my desktop where was my source .tex file. When I deleted (.sty file) it - everything is working just fine :) As user Werner says

TeX searches the local folder first before examining the FNDB for packages/document classes. As such, the older copy of cancel was used instead of the updated/installed newer version, causing the error. Once the local copy was removed, the updated style file could be accessed, solving the problem.