I have enabled the search function and it seems to work well. Sorry that it has sucked for so long.
The reason that the search function has not been working is that enabling it takes up a lot of database space. The hosting provider says they don't allow databases to be larger than 100MB. This forum takes up about 70MB without the search indexes, but well over 100MB with them. So today I just backed up the database and enabled search anyway. The database is currently about 135MB. If they call me out or the site stops working, I'll just turn off the search and I have the backup just in case. Hopefully the 100MB limit is bullshit, or they only really enforce it if you go WAY over the limit.
