mhh - bad news.
To the background: In Pages there are some templates. I took one of them (2-3 years ago) and redesigned it for my use. I didn't changed any Fonts. Some changes for borders etc - nothing more.
Before I installed the fresh Lion installation it works. On the harddisk was installed 10.2 - 10.7 (with all the upgrades).
My opinion is, that the Font is a part of the templates or a part of OS X 10.x. I have no problem to reinstall the font (all DVD's are working), but where should I start searching for the font ;-)
To buy the font is one way ... the last path.