Troubleshooting "Go To Page" Stopped Working?

I'm pretty sure I used to be able to open a pdf on the Kindle Dx, open the menu, select "go to," select "page," and awkwardly use the alt keys to type in the number.

Now I can't do that - the "go to" menu quits if I select "page"

I've had better luck using Librerator to read pdfs [and djvus!], but the Kindle's battery keeps running down, with Wifi disabled, so it'd be nice to use the basic Kindle system.