Time for some investigation. Set a breakpoint in your test at the line where it fails and then start examining the object tree in your app using the Object Browser. Follow along the Aliases chain
Aliases["Ascend"]
Aliases["Ascend"]["frmMDI"]
Aliases["Ascend"]["frmMDI"]["MdiClient"]
etc.
If any link is not reachable, determine why. Are the object recognition criteria correct? Has some recognition value changed since TestComplete recorded it? Perhaps TestComplete didn't choose an appropriate property for the recognition criteria. (A name is usually better than an index.)