If you double click a PDF file on your desktop, does Acrobat Reader X launch?
Is Acrobat Reader installed on this computer?
Using FileMaker 13 advanced on a Windows 7 system, I used insert file, store a reference, to insert a PDF file into a container field. When I double clicked the container field, Acrobat Reader 10 launched and opened the file.
Yes, Adobe Reader X is installed and apparently works properly (double-click on a PDF file from Windows Explorer launches as expected, as does typing a PDF file name at a command prompt). It is just Send Event and the "open automatically" features of FMP that were not working. I've not tried the container technique you used.
But you do bring up the possibility that the problem is an individual configuration issue. While Adobe Reader X reported that no updates were available, I uninstalled and re-installed it anyway. The Adobe re-installation routine installed Adobe Reader XI rather than X. And version XI does work properly with FMP 13 in my tests.
Updating to Adobe Reader XI is an acceptable solution for my use, so I am not going to pursue further what was happening with X.
I've not tried the container technique you used.
What I used should produce results identical to the methods you were trying to use. They all tell FileMaker to open the file using the OS system's "default application" specified for that file extension.