GUIDE seems to be based on a really old CAD software package like P-CAD, intended for drawing printed circuit boards (PCBs). Some bright spark took the netlist output and wrote some software to convert the netlist to C, which is then compiled. Have a look at Tools->ViewNetNames->Close and you'll see the PCB references in the names of the dialog buttons. Anyway, the printed output from such antique programs is raster, not a glyph from a font, so when you print it to PDF all you get is a graphic image, no searchable text. I tried this just for fun and confirmed the sad news.
I would not disagree with anyone who might think that it's about time they got with the 90's and introduced a proper search function, and while they're at it scalable OS fonts for text.
Update: If you change the font of anything from the default line-based "System" font to something TrueType or OpenType (e.g. Arial) then you get text in the PDF, not graphics, and those items in the PDF can be searched.