Apologies for replying to a very old post but I had signed up to the forums to ask a very similar question about runtime parameters before I found this and also fell into the same pitfall. I don't know if the documentation has changed since this was written, but to be clear the formatting should be:
<runtimeParameter>
<inputParameter>
<uiid>
guid from report definition
</uiid>
<inputValue>
value as prompted when running through the UI
</inputValue>
</inputParameter>
</runtimeParameter>
Note that it is "uiid" and not "uuid" and "inputValue" not "value". While these are now correct in the documentation, it is not immediately obvious where the problem was as the differences are minor between the documentation and the post above.
Since this is the top response on Google when searching for Hornbill and User Prompted Input, hopefully it can help others from making the same mistake.
