Arrow keys not working within text boxes

[snarfii]

I am running MS Word 2003 (11.5604.5606). I am working in a document with a many text boxes, essentially, a giant flow chart. Occasionally, when I add a new text box at the bottom of the document, type text in it, then use arrow keys to move the cursor around with the text, the cursor jumps out of the text box and into a different text box, usually on a different page. It only happens for the text box I just inserted and subsequently inserted text boxes, but within existing text boxes, the arrow keys work just the way they are supposed to. Any help greatly appreciated!

Thanks