I am having a problem with corrupt pdf files as well. I am running 7.34. the pdf files I attach to an email are corrupt and not readable. however, the regular export to pdf on local drive works fine, so one work-around is to save to pdf and then attach to an email. the other work around is to include the invoice in the text of the email.
I noticed that the file size on the exported version is 142 kb while the email version is only 105 kb. maybe there is a problem with the compression algorithm?
anyway, I gather by this thread that this is a known issue? checking in to see if there is a fix on the horizon.
thanks!