PHP and Wiki Error

[Venkatesh]

I am running MediaWiki 1.2.0 on my server for a FIRST-related group, and for the most part it works, albeit slowly. Mediawiki 1.2.0 is running under Windows XP, Apache 2.0.50, and PHP 5.

Occationally, I get an error, "Fatal Error: Class PHPTAL_DBResultIterator must implement interface Traversable as part of either Iterator or IteratorAggregate".

I have received this error under PHP 5 RC3 with Apache 1.3.31, PHP 5 RC3 with Apache 2.0.50, PHP5 final with Apache 2.0.50, and PHP 4.3.8 on Apache 1.3.31. Does anybody have any idea what this error is? And does anybody have any Wiki performance-enhancing tips?

Thanks