Hello, PHP 4.4.0 and the latest 5.0.5 both are currently in a state of 50/50.
ADODB has been upgraded to take the changes in these versions, however Smarty which is used by TikiWiki has not yet released a patched version.
You can only hide these error messages by using TikiWiki 1.9 and setting error_reporting_level in Admin->General to off.
Be aware this is only hiding the error messages and NOT fixing the problem.
1.9.2 will correct these issues, but at the moment we are waiting on a smarty release to upgrade to also. There is currently no timescale setout for a release.