Blocks are blacked-out when plotting to PDF

I am using autocad architecture 2012; the problem i am having is that when i pdf any sheet that contains a block, the plot prints the block/symbol completely filled with color (black).

when i pdf, the client (commercial) demands that we use the "DWG to PDF" setting, however this causes text throughout the sheets to convert into unreadable dashed lines, therefore our office has started to use "Adobe PDF" for all our pdfing needs. but now the blocks (mainly the title block tags, and keynote symbols) do not plot properly. I always preview the sheet before pdfing and it always looks normal... it seems like the problem occurs somewhere between the file and adobe acrobat x... is it possible for the verison of adobe to be the culprit?

please respond ASAP if you have any idea what I can do to fix this. thanks.

Is there a Background Mask or Wipeout on there?