FAQ/Setting the default browser
From AbiWiki
AbiWord does not use the Gnome specified default browser.
Rather it first looks for the environmental variable "BROWSER". If the program name described by the environmental variable does not exist, then it tries to run browsers in the following order:
1 konquerer 1 mozilla 1 netscape 1 kdehelp 1 lynx in an xterm
Using AbiWord with MozPlugger
Daniel Dekovic sent a modified MozPlugger configuration file ("mozpluggerrc") to the mailing list a while back. It enables Mozilla to display ABW, RTF, DOC, and SXW files using AbiWord.