Can you achieve what you want by working the UI without scripting?
There might be other conditions, that would prevent your inline frame to move.
Do you get an error message? If yes, tell us its exact contents.
Or is it "simply" not working?
I'm not too much into AppleScript, but shouldn't the anchored object settings of the anchored object be used instead of the parent of that object (which is a character)?
set anchor yoffset of anchored object settings of parent of item 1 of inline frame 1 to ofset
Please note: No idea, if my syntax is right reaching the first anchored obejct in that story!
Please note, that my syntax could be totally wrong.
This snippet works ...
tell application "Adobe InDesign CC 2014" set ofset to -5 tell active document tell story 1 tell text frame 1 set anchor yoffset of anchored object settings to ofset end tell end tell end tell end tell