I haven't tried it in a while, but AC's history has been hard-coded [BAD] third-party app calls such that anything other than Adobe fails.
AC *should* call the OS, and let the OS determine what app is registered to handle a given file type, but they don't - Yet.
For viewing PDFs, I much prefer something light-weight that isn't as prone to attacks like
Sumatra, a FREE eReader that handles multiple formats.
