If DTerm's windows are unexpectedly opening as generic:
Make sure the frontmost window actually reflects a local file or folder. A good rule of thumb is that it should show both an icon and filename in the title bar of the window, and show the path to the item in a popup menu if you command-click on the name.
If you are in an application besides the Finder, ensure that DTerm has access to the Accessibility APIs. See Using DTerm across different applications for details.
Try saving a text document in TextEdit.app, and then triggering DTerm. If you get a non-generic DTerm window set to the location of the text document, DTerm is functioning properly. It may be that the application you are having trouble with may be doing something that confuses the Accessibility system—you should contact the developer of the application, as Mac applications are expected to work with Accessibility.