Firstly: this is a community forum, with its members answering questions in their spare time: could be quick, but it can also take more time. For pressing matters I'd take up contact with Mendix directly.
Regarding your issue: Are you sure the attributes for the object you are viewing are not empty? and your user has the proper permission to read the data? A standard number input field should work, perhaps you can see if the object was properly retrieved, or something went wrong there?
A input widget is only editable if:
Possibly take a look to the rapid developer path to understand it a bit more: https://learn.mendix.com/link/path/10
When I check the properties for this type of widget in the debugger of Chrome, I can see the data for "value". So if you don't see any data it might be a permission problem as mentioned in the other anwers.
Maybe you can check the value with JQuery in the console of your debugger (I don't have any experience with Firebug, but it works in the Chrome debugger). Based on the information you posted, it should look like this:
May I ask what you are trying to automate? If it's about testing you might want to consider ATS (https://www.mendix.com/security-and-quality/#atsContent).