(PS: If _anyone_ can get the small stylus keyboard (not the full-screen thumb keyboard) up in this version, please tell me how! That has the potential to lead right to the bug!)
Tapping in the editable text area does not open the stylus keyboard on an N800. In order to use this AbiWord on the N800 with the stylus keyboard, you must open the stylus keyboard (in an app that lets you do it) and choose the button with the page in the lower left corner of the keyboard. Choose Tools -> Settings, then uncheck "Launch finger keyboard with [square]". Then, in AbiWord, you hit the middle of the D-Pad to pop up the stylus keyboard...
It's in the first post - take a look at it before asking about something that doesn't work right and your question might be answered before being asked.