Bug#601237: Bug is still present
I can reproduce the bug on Wheezy. I also managed to narrow down the cause, with the help of "texdoc -d pgfmanual".
The culprit is the way xdg-open is invoked, which is asyncronously. Texdoc runs "xdg-open filename; rm -f filename", and the file is deleted before the pdf viewer gets a hold of it. A work around is to set a pdf viewer in a texdoc configuration file as explained in http://tex.stackexchange.com/q/260/1630 That way bypasses xdg-open, and thus works synchronously.
I hope this helps.
Reply to: