Non-PDF special ignored!

This is a PDFTeX error: PDFTeX is running in PDF output mode, and it has encountered a \special command. PDFTeX is able to generate its own output, and in this mode of operation has no need of \special commands (which allow the user to pass information to the driver being used to generate output).

Why does this happen? LaTeX users, nowadays, hardly ever use \special commands on their own — they employ packages to do the job for them. Some packages will generate \special commands however they are invoked: pstricks is an example (it’s very raison d’être is to emit PostScript code in a sequence of \special commands). Pstricks may be dealt with by other means (the pdftricks package offers a usable technique).

More amenable to correction, but more confusing, are packages (such as color, graphics and hyperref) that specify a “driver”. These packages have plug-in modules that determine what \special (or other commands) are needed to generate any given effect: the pdftex driver for such packages knows not to generate \special commands. In most circumstances, you can let the system itself choose which driver you need; in this case everything will act properly when you switch to using PDFLaTeX. If you’ve been using dvips (and specifying the dvips driver) or dvipdfm (for which you have to specify the driver), and decide to try PDFLaTeX, you must remove the dvips or dvipdfm driver specification from the package options, and let the system recognise which driver is needed.