There are many things you can do to have webservice installed on the windows server. In case you are planning to use the IIS then it is better you follow the instruction in the IIS section. Since Dokuwiki does not use any database engine it is enough to have only php working smoothly with IIS.
But, if you are looking at the alternative web service for small network or local use you can look at many of the available solutions to enable Apache with PHP support.
There are many WAMP solutions available for free download and they can enable the php with apache out with small installation. Comparison among them can be found on wikipedia.
However following are some of the WAMP on which dokuwiki is reported to have worked satisfactory:
Besides Apache, there is also QuickPHP, a tiny installation-free webserver/php combination.
Perfect for a small DokuWiki on a USB-Stick, for example.