Not reproduced with Inkscape 0.48.1, 0.48.2 (both 32bit, cairo 1.10.2) and Inkscape 0.48.3.1 (64bit, cairo 1.12.2) on OS X 10.7.4, using default PDF export options (I don't appear to have most of the used fonts installed on my system, but for now did not spend the time to investigate which ones exactly are missing, and which of those would be freely available for download and use).
Could you please provide information about your OS/platform, and which PDF export options you use for the poster?
Not reproduced with Inkscape 0.48.1, 0.48.2 (both 32bit, cairo 1.10.2) and Inkscape 0.48.3.1 (64bit, cairo 1.12.2) on OS X 10.7.4, using default PDF export options (I don't appear to have most of the used fonts installed on my system, but for now did not spend the time to investigate which ones exactly are missing, and which of those would be freely available for download and use).
Could you please provide information about your OS/platform, and which PDF export options you use for the poster?