TikiWiki uses an ADODB layer to talk to the database, this layer in version 1.8 of TikiWiki is not compatible with MySQL 4.1. The ADODB version used in TikiWiki 1.9 does support 4.1 however:
MySQL brought in some changes that affects the SQL syntax to particular the LIMIT which we use. You can see various bugreports at http://sourceforge.net/tracker/?group_id=64258&atid=506846. MySQL 4.1 support will probably happen with 1.9 release but it is still very experimental and no real fix has been issued.
For now, all I can say is to look at alternative hosts: TikiFriendlyHosts