Error: missing font metrics file

Font metric file for font missing. You must have AFM font metric files intalled on your server in order to use the PS output method. Metric files may be taken from Ghostscript distribution. (Note that you do NOT need the Ghostscript itself).

Metric files are not installed on your server Install either ghostscript-fonts or any other Type1 font package containing metric files. Edit .html2ps.config and to point to installed metric files.
The TYPE1_FONTS_REPOSITORY points to incorrect directory. Edit; set the value of TYPE1_FONTS_REPOSITORY to directory where your font metric files reside.
You have no requested metric file. Probably you're using non-standard font package. HTML2PS is configured to work with fonts distributed with Ghostscript out-of-the-box. If you're using other fonts, edit .html2ps.config. metrics items should contain names of metric files you're using.
You've forgot to register the AFM metric file for this font. Register the metric file according to the HOWTO: Install custom fonts.
AFM file is not readable by the script. Check if AFM file permissions allow this file to be read by all user accouts (or, at least, the user accout PHP is running on).
PHP safe_mode open_base_dir restriction prevents AFM file to be opened. Copy AFM files to any available directory under the 'open_base_dir'. An alternative approach is to disable 'safe_mode'.