This patch is intended to fix a very severe bug* which persists even in the most recent version of xpdf, the otherwise-great PDF viewer. This bug disables the copy and print features of xpdf and renders pdftotext completely useless for certain PDF documents. Please contact me if you know of other open source PDF viewers which place such restrictions on users against their will, and I will make mention of them here.
Download the patch here.
* I am aware that the developer of xpdf deliberately placed this bug in xpdf and indeed, considers it a feature. However, any 'feature' which deliberately prevents the user from doing something he's likely to want to do is not a feature, but a bug. Such 'features' are contrary to the nature and spirit of free software.