Yes, iMovie 10.1.6 and iDVD 7.1.2 are compatible. Share out your movie from iMovie to your desktop using the File export option (see last paragraph below). Then open iDVD and create a project. Drag your movie into the edge of the project screen main window, being careful not to drop it into a drop zone for pictures or videos in the theme. That will load the movie into iDVD.
Once you are finished with your iDVD project, click on File/Save as Disc Image. After the rendering is complete (it will take a few minutes) the disc image icon will appear on your desktop. Click on the icon to play the movie to make sure that the rendering was done correctly. If all is good, insert a DVD-R standard single level disc into your internal or external burner. Then, control click on the disk image icon that appears on your desktop and click on Burn Disc in the drop down menu that appears. In the burn settings that appear, choose 4x speed and click on Burn. Depending on the size of your project your disc will burn in a few minutes or so. You can burn over and over again from the same disc image icon to create as many DVDs as you want.
The duration limitation of a movie in iDVD when burning a single level standard DVD is two hours duration. That includes your menus and any photos or videos that you inserted in your menu links.
In iMovie, the share drop down menu can be reached by clicking on File in the main menu, and then Share/File in the drop down menu that appears. Or, you can click on the share icon (the little box with an upward pointing arrow in it) located in the upper right corner of the project screen and a box will appear giving you share options. Choose File as the share option.
-- Rich