Forum Moderators: open
If your pages (or your changes) were added after approximately February 12th, then they were listed only because of the action of Google's freshbot.
If freshbot picks up your pages again, they may show up for a few days and then disappear again. Each time freshbot visits, this cycle repeats. Then, after the next monthly update and barring any problems with your pages, your pages will stay in the index.
The frequency of freshbot visits is dependent on your page rank (or your predicted page rank) and on how often you significantly update the pages. PR4 pages and above which are kept up-to-date usually can stay in the index. (I would warn you not to manufacture changes just to keep freshbot visiting - If the deep-crawler comes by and archives one of your "bait versions", then that will be the page it uses to rank your site for all of next month!)
Check out the Google Knowledgebase (see link at the top of the WebmasterWorld Google News forum), and also try a site search for "freshbot" and "everflux" here on WebmasterWorld.
HTH,
Jim
It's worth a try. While waiting to light the next piece of incense, work on getting more incoming links with on-topic link text from relevant sites which have decent PR. Also work on creating content which will make other sites want to link to yours without being asked. One or more of these techniques - incense, links, and content, will probably help. :)
Jim