Hello!
I won't be any help, but just a thought.
Try another pdf file to check if the TTS is possible with pdf at all. But you have to check first if the text on your pdf file is readable/copyable by your computer (can you highlight it?) or is it just an image? TTS won't read pdf which is made of scanned images until you will make a proper OCR scan, which means to extract text from the image. You usually need special software to do it and the outcome depends on the quality of the scanned files.
Here you have an example of pdf file with extract text to check TTS on your device:
http://fzs.sve-mo.ba/sites/default/f...sti/sample.pdf
Good luck!