It's a good bug report posting, so I'll move it to the Tekkit Bug Board where it belongs.
Now, there are two things that could have gone wrong, either of which is just as likely:
1) Your server crashed, either by a power cycle or simply a Java error, without saving correctly. You will need to a) load the world from a backup, load the world in MCEdit and save over it, accepting that you may have some chunk errors, or c) see about a map repair program if you have no backup or the backup is too old to be of use to you.
2) You have a massive item spill somewhere. This can be cleaned up by an item removal tool like WorldEdit (installed on the server) or a lag-reducing plugin that does it for you. Once the items are gone, you'll need to find out the source of the spill (usually a quarry or pipe (not tube) network) and fix it.