I have been playing around with the 2.4.1 version of Spark and installed some Adium emoticon packs. Of the ones I tried, most were fine but the Giga Smileys (which I believe are some BIG ones) wouldn’'t show in the preview window under Appearance (they did install fine). Selecting them as the current smiley set resulted in not being able to open any chat windows and I could not get back to the appearance section of preferences.
Attempting to do so did select the Appearances icon but the right hand pane remained as the previous section (e.g. chat, login, sounds etc).
To resolve this I had to move the smileys folder from the emoticons dir and duplicate the default one and give it the Giga folder name. Then I could get back in and change it and then manually delete the Giga folder to remove it completely.
I haven’'t tried this with beta 2.
Incidentally is there a spark way to remove icon sets you don’'t want anymore?
Hope this was helpful