Hmm. Okay, my understanding of how the system associates apps might be incorrect. Lizard's suggestion should work, I was just hoping you could do it in a cleaner fashion.
Do you still have the old version of OmniFocus installed anywhere on your system?
By the way, you need to replace things like this:
Code:
-- Add waiting for context task to OmniFocus
tell application "OmniFocus"
with
Code:
tell application id "com.omnigroup.omnifocus.macappstore"
There are some scripts that use
Code:
tell application id "com.omnigroup.omnifocus"
instead of
Code:
tell application "OmniFocus"
but either way, you need to change the tell application blocks to the form suggested by Lizard.