I've tried on Windows 7 64-bit and Windows 10 64-bit. I get this LocalService.dll error whenever I try to launch the portable version.
If I have FoxIt Reader (portable) already running, the PDF open fine.
I've tried to open attachments from Windows 10 Mail and Windows 7 Outlook 2013 FYI.
Perhaps with the 9.4 security update, this can be looked at too?
I was able to get LocalService.dll from the enterprise MSI of 9.3 .
Initially, I was given a download for 9.4, but I looked at the Portable Apps version and tried that instead in the URL:
I was able to extract all the files in the MSI to a directory:
msiexec /a msifilepath/qb TARGETDIR=targetpath
I confirmed that \Foxit Software\Foxit Reader\FoxitReader.exe is indeed 126.96.36.19926
Anyway, I copied the \Foxit Software\Foxit Reader\LocalService.dll
to portapps \FoxitReader\App\Foxit Reader directory.
Now, the error goes away.