# Illegal Parameter with Biblatex

I am getting some Error when I try to compile my Latex File and I have no clue why.

``````  ! Illegal parameter number in definition of \NewValue.<to be read again>W ...Documentation (last accessed: xx-xx-2015)}
! You can't use `macro parameter character #' in horizontal mode.<argument> ....com/essays/axxx.htm##WhenToxxxxx ... ...tbibliography[title=Literatur]
``````

and

``````       ! ngerman: The command "g is undefined.\grmn@dq@error ...and \dq \string #1 is undefined} ...d, dieses Vorgehen wird "xxxx" g
! Illegal parameter number in definition of \abx@field@howpublished.<to be read again>W xxxW. xxxx (\cite{master})
``````

I am net even sure if it has todo with Biblatex, but the (last acc....) is a part of my external BibLatex Entries. The strange thing is, that the output says that the Error is in line 33 - which is an %comment , the first one after `\mainmatter`

And many more of that kind.

``````            @MISC{master,

TITLE = "Quality ",
HOWPUBLISHED = "http......... (lastaccessed: xx-xx-2015)",
YEAR="2012",
}
``````

I would like to show some Source Code, but the Lines where the Error appears are mostly Comments and the parts, where its not an comment it´s in the Error.

Can anyone explain me what´s wront, please?

Edit:

``````\documentclass[runningheads,a4paper]{llncs}
\usepackage[ngerman]{babel}
\usepackage[
backend=biber,
style=numeric,
]{biblatex}
\usepackage{url}

\mainmatter
%first the title is needed  error//! Illegal parameter number in definition of \NewValue.<to be read again>W ...Doc(last accessed: xx-xx-2015)}

\author{ffff}  //! Illegal parameter number in definition of \abx@field@howpublished.<to be read again>W \endentry

%  //! Illegal parameter number in definition of \abx@field@howpublished.<to be read again>W \entry{when}{misc}{}

xxxxx x. xxx(\cite{when}) schreibt, dass ////! Illegal parameter number in definition of \abx@field@howpublished.<to be read again>xxxxx x. xxx (\cite{when}) schreibt, dass
\printbibliography[title=Literatur]  //! You can't use `macro parameter character #' in horizontal mode.<argument> ....com/essays/axxx.htm##WhenToxxxxx ... ...tbibliography[title=Literatur]

@MISC{when,
AUTHOR = "xxxx x. xxx",
TITLE = "",
}
``````

Well, I hope that helps, I wrote the line and after the // the Errormessage for this Line.

• It's impossible to attempt a diagnosis with so few data, sorry. – egreg May 13 '15 at 21:16
• A good question will include a complete (but minimal) document that will reproduce the error. If you don't provide that, is it reasonable to suppose that others can suggest how to fix the error? For bibliography-related errors, you might need to provide a `.tex` file and a few (problematic) entries from your `.bib` file. You haven't even provided a complete `.bib` entry at this point! – jon May 14 '15 at 1:56
• It really, really is hard to figure out exactly what is wrong because you left out quite a bit of necessary information (the bib entry is not complete), but to me it seems the trouble is with the URL, it seems to contain a `#` which must be escaped, load the `url` packages and wrap the URL in a `\url{...}` command. You can do even better if you use a bibliography packages/style that supports URLs, then you would just go with `url = {htp://example.org}, urldate={2015-06-06}` (this example would work with `biblatex`). – moewe May 14 '15 at 7:50
• Yes, I can understand that. But I have already 10 sites and it was working a long timeand now I added some \cite and nothing is working anymore. I edit the post so that you can maybe see something. – Scoooby May 14 '15 at 14:33

The problem is that there is an `#` in the argument of `howpublished` field. In biblatex `howpublished` is consider plain text and not as literal.

The best solution would be to put URL in the `URL` field and to use the biblatex `@online` entry type:

``````@online{when,
AUTHOR = "xxxx x. xxx",
TITLE = "",
Alternatively, you can escape `#`, that it use `link\#anchor` in the `howpublished` field.