While working on the Shared Photo Gallery Template, I ran into similar issues. I can't find any way to generate Wikidot-compatible [[embed]]...[[/embed]] code on Photobucket (the only reference to a "widget" I found was from a 2006 entry on the Photobucket blog). I ended up opting for an iframe/html code block solution. I suspect Photobucket still supports the old embed code but they don't seem to provide the code in that format for any newer albums or slideshows.
If you have a number of Photobucket albums to display, you may want to borrow some of the code from the template.
-Ed
iframe code
[[=]]
[[iframe http://YOUR-WIKI.wikidot.com/YOUR-PAGE/code/1 frameborder="0" scrolling="no" width="660px" height="550px"]]
[[/=]]
html code block
[!--
[[code type="html"]]
@div style="width:640px;text-align:right;"><embed width="640" height="480" src="http://static.pbsrc.com/flash/rss_slideshow.swf?rssFeed=http%3A%2F%2Ffeed635.photobucket.com%2Falbums%2Fuu74%2Fpizzageek%2Ffeed.rss" type="application/x-shockwave-flash" wmode="transparent" /><a href="http://photobucket.com/redirect/album?showShareLB=1" target="_blank"><img src="http://pic.pbsrc.com/share/icons/embed/btn_geturs.gif" style="border:none;" /></a><a href="http://s635.photobucket.com/albums/uu74/pizzageek/" target="_blank"><img src="http://pic.pbsrc.com/share/icons/embed/btn_viewall.gif" style="border:none;" /></a></div@
[[/code]]
--]