I'm revamping a survey form for my company, and we started by taking the old form, scanning it as a PDF, and exporting it as a Word file. Most of the errors created in the transition process I've been able to fix, but there's one that's still puzzling me, and that's this line inbetween two lines of text: http://i.imgur.com/E9jIs.jpg

Unlike other lines that appeared, I can't click on it to delete it. Double-clicking brings up the margin menu, which I honestly know little about and don't know what to tinker with. What should I adjust so that this line is deleted or becomes invisible?

The line looks like a table cell border but could be some other kind of border. You may want to look at Weird Lines and Borders

Converted documents, whether from image files, pdf, or another word processing program, are seldom what you want to use for production documents. You especially do not want to use them for templates. They will have very complex formatting and be difficult to edit.