NNOIDONE that happened to me, too...what I did was go to "get info" and in the "open with" drop down menu where it says "toast", use the down arrow to find...I think it's "disk installer" or something like that...and make that the default app for opening this file...BUT...even after I did that, though gifbuilder installed, IT DIDNT WORK! I even repaired/verified disk permissions (which works with some apps, like mail) and restarted it a couple times, but it still didn't work :( I used it before, on early versions of osx, but it doesn't seem to work with osx 10.4.7 :( and the guy who wrote it says he won't be updating it :(
(Version 1.0)